GROUNDWATER OF THE BARZAS DISTRICT OF THE KUZBASS.

P. M. Bolshakov.

Introduction.

The present article is the first summary of hydrogeological materials for the Barzas district, which possesses significant reserves of sapromixite coals and is of interest with respect to possible oil-bearing capacity. In connection with the clarification of the oil-bearing capacity of the geological formations of the district, the West Siberian Geological Administration is carrying out deep drilling near the settlement of Nevsky.

The summary covers the six-year period of hydrogeological work carried out by the WSGA from 1932 through 1937 inclusive, and presents the results obtained on the question under consideration. Let us note the principal works that formed the basis for the characterization of the groundwater of the district.

The beginning of groundwater investigations was laid in 1932 by A. A. Shkaranda (9), who carried out a hydrogeological survey on the territory of the Barzas mine and hydrometric observations in cable-tool drilled boreholes. In 1934 analogous investigations were resumed by B. K. Dunaev and were then continued by the author of the article until the end of 1935. The largest hydrogeological works (survey, reconnaissance, and hydrometric) were carried out in 1935. They covered the mine fields of the Barzas mine and, in part, the area of the settlement of Nevsky. The materials of the 1935 investigations (2) served as the principal basis for compiling the present summary. The characterization of the hydrogeological conditions of the southern and northern parts of the district is based on data collected by A. V. Tyzhnov during geological mapping (springs Nos. 46 to 57) and obtained during incidental hydrometric observations in cable-tool drilled boreholes. Unfortunately, the summary has not yet included unsampled data from hydrometric observations in deep boreholes laid down by the WSGA near the settlement of Nevsky.

Brief physico-geographical sketch.

1. Orography and geomorphology.

The Barzas district, encompassing the northeastern margin of the Kuznetsk coal basin, has the following geo-

geographic coordinates: 55°53′—55°34′ N lat. and 86°10′—86°25′ E long. (from Greenwich). Orographically, the area studied is a low-mountain taiga landscape, considerably dissected by a dense network of rivers and ravines. The highest points of the relief are confined to the southwestern parts of the area, where they reach an absolute elevation of 365 m (Mount Krasnaya), from which, to the west and north, the surface gradually descends to 200 m and lower. The most lowered parts are the valleys of the rivers Yaya and Barzas. Thus, for example, the elevation of the water edge at the mouth of the Barzas River is 165 m. The difference between the maximum and minimum elevations is 200 m of relative height.

The hydrographic network is represented by the Yaya River, flowing in the north of the district, and by its right tributaries—the Kaigur, Barzas, and Tuganakovskii Kelbes rivers. The direction of river flow is controlled by the slope of the terrain and by the geological structure. The large water arteries of the district—the Barzas, T. Kelbes, and Kaigur rivers—having a northward tendency, are for the most part laid along the strike of the geological structure. Conversely, their tributaries cut the structure across its strike. The Yaya River, from the mouth of the Kaigur to the mouth of the Kelbes, flows across the structure, and below and above the points noted—along the strike of the latter.

The watershed spaces of the district are mainly remnants of an ancient peneplain, usually rather well expressed (6). Of considerable interest is the watershed between the Barzas River and the Tuganakovskii Kelbes. Here the relief of the ancient peneplain preserves a leveled or undulating surface, complicated by the modern hydrographic network. From the mean leveled surface of the watershed under consideration, a slope is observed to the west, i.e., toward the Barzas River, and to the east—toward the Tuganakovskii Kelbes. According to A. V. Tyzhnov (6), the peneplain of the right bank of the Barzas River is covered by loesslike loam lying on weathered bedrock. The thickness of these loams varies; in places, however, the weathered bedrock appears directly at the surface, as occurs in the area of Krasnaya Gora and at some other points. Prospecting workings laid out by M. M. Finkelshtein (8) in the upper reaches of the Omutnaya River likewise showed an insignificant thickness (2–3 m) of the loesslike cover resting on weathered bedrock of the Cambro-Silurian, developed within the watershed space. With the rocks of this peneplain, apparently, are associated the scatterings of quartzite boulders encountered at the heads of many ravines.

The main rivers of the district mentioned above have broad valleys with gentle and sodded slopes, the steepness of which increases toward the foot. On the slopes of these valleys there occur two clearly expressed accumulative terraces, composed of sandy-clayey and gravelly formations.

The first floodplain terrace is widespread, with a height of up to 5–6 m above the low-water level of the rivers. It has a considerable width, in places (the Barzas River) reaching 2–2.5 km. Its surface is characterized by a large number of oxbow lakes and lakes, as well as by waterlogging.

The second terrace has a height of up to 9–12 or more meters above the river, a width of 0.7 km, and an undulating surface. This terrace often pinches out and is less developed than the floodplain.

The tributaries of the main rivers in most cases are characterized by asymmetry of their valleys in transverse profile and by a nearly latitudinal direction. The asymmetry of the transverse profile of the valleys is evidently due to the different exposure of their slopes. As a rule, the southern and western slopes of these valleys are steeper and more exposed than the northern and eastern ones, which are gentle and covered by loesslike loams.

The upper reaches of the tributaries are characterized by a V-shaped transverse profile of the valleys, which are deeply incised into the loose deposits of the ancient peneplain and at times also expose the weathered bedrock underlying these deposits (6).

The dominant part of the investigated area belongs to the basin of the Barzas River. The upper reaches of this river are situated in the foothills of the Kuznetsk Alatau, and its course is generally meridional; within the limits of the sheet under consideration, however, the river enters only with its middle and lower courses. Throughout this entire stretch it has a well-developed and wide valley, in which the right slope is steeper and higher than the left. The tributaries of the Barzas River in the described sector are the Poludennyi Shurap, Kedrovka 2nd, Omutnaya, M. Tokovaya, B. Tokovaya, Vasilievka, Dedushkina Rechka, and others.

The climate of the region may be called sharply continental. The mean annual amount of atmospheric precipitation is 594 mm, of which 380 mm falls as summer precipitation and 214 mm as winter precipitation.

The annual evaporation from a water surface is 40–55 mm. The frosty winter promotes freezing of the soil to a depth of approximately 1 m.

A considerable amount of atmospheric precipitation, most of which falls in the form of prolonged rains, and slight evaporation are favorable factors for the accumulation of groundwater resources.

Deep freezing of the soil and the fall of snow usually onto frozen ground slow the infiltration of precipitation and spring meltwater into the depths and, conversely, intensify surface runoff in spring, thereby causing a large flood in the rivers of the region (2).

2. Regime of the rivers.

The mountainous-taiga landscape and the sharply continental climate of the region impart a distinctive character to the hydrolo-

hydrological regime of the rivers of the district. The regime of surface watercourses has not yet been sufficiently studied, but, nevertheless, its main elements, such as the occurrence of spring floods and freshets, fluctuations of water levels and discharges, have been established. With respect to these elements of the regime, let us consider the characteristics of the Barzas River and its tributaries.

At the end of April—beginning of May, the spring flood appears on the Barzas River, when water levels rise 3–4 m above the low-water level and the river overflows its banks, inundating a considerable part of the floodplain. The greatest flood was observed in the spring of 1935, when the water level rose by 6.90 m (station No. 1). During this period the entire floodplain was covered with water.

In addition to the greatest spring flood, formed by the rapid runoff of spring meltwaters over frozen soil¹), summer and autumn freshets occur, following the fall of abundant atmospheric precipitation. Summer freshets are timed to the last days of June and August, autumn ones to September, with the September freshet being considered the greatest of them. Rarely, as was observed in 1935, a late autumn freshet occurs, falling at the end of October. Incidentally, we emphasize that freshet periods are of short duration. In drought (the first half of June) and in wintertime (from December to March), minimum water levels are established. In connection with fluctuations of the levels, the discharges of water in the river also change considerably; these can be judged from measurements at the Barzas mine. During the spring flood, water discharges reach 15–27 m³/sec. (9); during low water they are expressed by an average value of 2–3 m³/sec. In summer the minimum discharges are 1.4–1.5, and in winter—1.19 m³/sec. (16, 11, 35).

The tributaries of the Barzas River—the small rivers Poludennaia Shura, Vasilievka, Kolokoltsovka, and others—are, in their regime, basically analogous to the Barzas. Only they react more sharply than the Barzas to the fall of atmospheric precipitation. In them, immediately after rains pass, especially downpours, water levels and discharges rise rapidly. This is most clearly manifested in the regime of the small river Kolokoltsovka, in which discharges, counting from drought to the period of rains, increase from 0.4 to 7.2 l/sec., i.e., 18-fold. The most typical discharges of the rivers of the district are given in Table 1.

Outline of the geological structure.

The Barzas district, insignificant in area, includes an extraordinarily great variety of rocks both in age and in lithological composition.

A. V. Tyzhnov (6) distinguishes for the district three principal complexes of geological formations, which differ sharply from one another

¹) Complete thawing of the soil occurs in May.

Table 1.

Hydrometric data

from one another in conditions of occurrence and degree of dislocation.

First complex. To it belong the ancient, strongly dislocated and steeply dipping rocks of the Kuznetsk Alatau, namely the Cambro-Silurian and possibly the Proterozoic. They are distributed over a considerable part of the watershed (peneplain) between the Kelbes and Barzas rivers, where they are represented by fractured metamorphic schists, sandstones, conglomerates, marbles, microquartzites, and diabases. In the indicated area the complex of ancient rocks is confined to the highest points of the surface. Westward, the surface elevations of the Cambro-Silurian gradually decrease and are hidden beneath a cover of younger formations.

Second complex. The ancient rocks form that rigid basement upon which the rocks of the second complex lie more tranquilly; these begin here with the Devonian, above which follow the Lower Carboniferous rocks and the coal-bearing suites of the Kuznetsk Basin. The entire western part of the area is characterized by the development of the second rock complex. Of these, the Devonian deposits, which are widely developed, extend as a meridional belt from the village of Yaya-Petropavlovskoye in the north to the Barzas mine and farther south to the settlement of Dmitriyevsky. In composition the Devonian is divided into two parts: lower and upper.

The lower series (the Krasnogorsk, Dmitriyevsko-Pereboi, effusive-tuffaceous, Barzas, and lower variegated series), including the Lower and Middle Devonian, is composed of beds of argillites, conglomerates, more rarely bituminous limestones, and igneous rocks (diabases and basalts), with rare seams of sapromyxite coals and combustible shales. These beds are representatives of a lagoonal-continental facies with a thickness of more than 800 m.

The upper series (the Famenian horizon, the middle variegated series, the Monstrovyi horizon, the Trelongus horizon, and the upper variegated series) belongs to the Upper Devonian, which for the most part is composed of marine nearshore sediments (limestones, sandstones, conglomerates, etc.) and, to a lesser extent, of variegated rocks (argillites, sandstones, and conglomerates). The thickness of the upper series varies from 135 to 800 m.

The Lower Carboniferous rocks are represented by marine deposits developed over a limited area. They begin with a member of green argillites, above which successively occur porcelain-like sandstones, Balakhonka and Perfilshino limestones, and they end with green sandstones and argillites. The total thickness of the Lower Carboniferous is more than 300 m.

The sediments of the productive series of the Kuznetsk Basin in the area include the Ostrog suite ($H_0$) and the Balakhonka suite ($H_1$), confined to the far western and partly to the northern parts of the area—

area of the Barzas district. The deposits of the suite include a thickness of sandstones, argillites, and conglomerates with coal seams.

The third complex of rocks contains Tertiary and Quaternary formations, lying unconformably upon the first two and represented for the most part by loose varieties. Tertiary deposits (clays, bauxites, conglomerates, etc.) occur in patches on areas of the ancient peneplain. Quaternary loose accumulations are developed along river valleys, gullies, and watershed slopes, being expressed as clays, loess-like loams, sands, pebble beds, and deluvial loams with an admixture of coarse-fragmental rubble.

Tectonics. The principal tectonic elements determining the hydrogeological features of the district are the following.

1) A high degree of dislocation and fine fracturing of the Cambro-Silurian deeply metamorphosed rocks.

2) Gentle plicative folding of the Devonian and younger formations. In the north of the district the southern end of the Anzhero-Sudzhensk syncline has been traced. The eastern limb of this syncline is characterized by a gentle (15–20°) dip to the west of the Devonian and younger rocks. The limb is traced from the north to the 2nd deposit. In the axial part of the fold a disjunctive disturbance has been recorded. Southward this syncline is lost in the ancient Cambro-Silurian rocks.

To the west, the Neva anticline adjoins the indicated syncline; it is the principal one for the Barzas district. In most sections, especially in the territory of the settlement of Nevsky, this fold shows a complex structure; it is often divided by an additional syncline into two parts—western and eastern; moreover, longitudinal disturbances have been established in it. The axial line of the Neva anticline is directed from SSW to NNW. The noted additional syncline is traced as far as the latitude of Dedushkina Gora, where it dies out, and appears again south of the settlement of Vagera. From Dedushkina Gora to the settlement of Vagera, essentially only the western limb of the Neva anticline extends, while its eastern limb is lost in the ancient rocks. In connection with this, almost all the mine fields of the Barzas mine are situated on the western limb of the main Neva anticline. The dip of the beds of the western limb is not uniform. In the area of the 2nd mine field the dip is gentle (15–20°), while farther south, in the 1st mine field, where there is a disjunctive disturbance, the dip of the rocks becomes steeper, reaching on average up to 25–30° to the west. The stratigraphic relationship and tectonics of the geological formations of the district are shown on the schematic section (Fig. 1), which was compiled for the latitude of the Barzas mine. From examination of the section it follows that, moving from west to east, a replacement of geological formations from younger to more ancient is traced. At the same time, beginning from the Barzas River to the eastern boun—

Geological section along line A–A
(after A. V. Mynnov)
Scale
hor.
vert.

1—limestones and sandstones. 2—argillites, sandstones, conglomerates, limestones. 3—argillites, sandstones, conglomerates. 4—argillites, sandstones, conglomerates, basalts. 5—microquartzites, shales, sandstones. 6—tectonic disturbance.

Fig. 1.

Geological section of the valley of the Borzovka River
along line 1–1

Scale
hor.
vert.

Water level in the boreholes shown as of 4/VIII 35.

1—peat; 2—loesslike loams; 3—banded clays; 4—pebbles; 5—gravel; 6—gravelly clays; 7—bedrock; 8—coal; 9—line of the piezometric surface; 10—water saturation.

Fig. 2.

at the boundary of the planation surface; a steady rise is observed in the hypsometric elevations of the outcrop surface of the Lower Devonian strata. Along the eastern margin of these strata the elevations reach 300 m absolute height, which, above the water level of the Barzas River, constitutes a relative excess of 130 m.

Analysis of core material from boreholes and observations in the Barzas Mine I showed that the Lower Devonian strata are enriched with microtectonic elements. Among these we note slickensides dipping steeply to the west, and cleavage cracks, which in places are completely, and in places only partly, filled with calcite and small crystals of pyrite.

The confinement of the outcrops of the Devonian strata to the high hypsometric elevations of the right bank of the Barzas River, and the westward dip of the strata, are favorable factors for the formation and circulation of artesian groundwater in the Devonian of the Barzas district.

Types of Groundwater.

The study of the hydrogeological conditions of the Barzas district is not complete. The investigations of 1932—1937 covered limited areas of development of the coal-bearing strata of the Kuzbass and the Kemerovo sill. In connection with this, the classification of groundwater types in the district proposed below is schematic.

On the basis of geological, hydrological, and topographic features, for the Barzas district we distinguish seven types of groundwater (Fig. 2).

1. Groundwater of loose rocks.

The Quaternary formations of the district include three varieties of groundwater—a) perched waters, b) deluvial waters, and c) alluvial waters.

a) Perched waters.

To this variety of groundwater belongs the first (from the surface) aquifer, which does not have continuous development. Perched waters occur on watershed areas in loess-like soils and in the cover layers of river-terrace deposits, where they are confined to peat bogs, loams, and sandy clays.

Perched waters attain especially great development within the floodplain terraces of the Barzas, Ya, and other rivers, occurring at a depth of 0.5—2 m from the ground surface. In places the waters emerge directly onto the ground surface, thereby partly causing the widespread development of bogginess on the floodplains. Only along the edges of the floodplain terraces, owing to natural drainage, do the perched waters occur at a considerably greater depth or even disappear entirely.

To a lesser extent, the waters under consideration are developed on the second terrace and on the watersheds, where the depth of their occurrence reaches on average 4–5 m. According to B. K. Dunaev, perched waters of watershed areas may communicate with the waters of the bedrock. Such communication is possible where the loess-like soils underlain by weathered bedrock are of small thickness.

According to the data from the sinking of test pit No. 1-bis and from drilling, the perched waters of the floodplain have a meager discharge, which does not exceed 0.01 l/sec (2).

The formation of perched waters on watershed elevations is due to the infiltration of local atmospheric precipitation. Two factors participate in the formation of perched waters developed in the valleys of the main rivers of the district.

The first and principal factor feeding these perched waters should be considered the infiltration of local atmospheric precipitation, favored by the large amount of the latter (594 mm per year) and by their unregulated surface runoff. The second, nonpermanent factor is the surface waters (the Barzas, Ya, and other rivers), which during the flood period inundate the surface of the floodplain and, within its limits, may promote the formation of perched waters.

b) Deluvial waters.

This variety of groundwater is not extensively developed and occurs less often than perched waters.

Deluvial waters are confined to coarse-clastic material (gravel, etc.) situated on slopes and at the foot of slopes.

The depth of occurrence of the waters noted is characterized by great variability. In areas where the coarse-clastic deluvium is not covered by a loess-like mantle, the waters occur at shallow depth and often, in the form of a series of springs (Nos. 1, 2, 3, 12, 27, 28, 48, etc.), emerge at the land surface with a discharge from 0.01 (spring 12) to 0.1 l/sec (spring 48) and a water temperature of 6–10°¹). In areas of gentle slopes covered by thick loess-like loam, deluvial waters occur at a considerably greater depth and are detected only by prospecting works. Their greatest depth of occurrence is 13.90 m (hydrogeological borehole No. 48).

In separate areas where deluvial material has accumulated in sufficient quantity, deluvial waters are concentrated in aquifer horizons. Thus, for example, prospecting works (ditches and shallow pits) carried out by A. V. Tyzhnov along the valley of the Studenaya River proved the presence of an aquifer horizon in the deluvium of the right bank of the indicated river.

¹) Water temperature is given in degrees Celsius.

A similar picture of the manifestation of deluvial aquifers occurs along the slopes of the valley of the Barzas River. They were found in hydrogeological boreholes Nos. 31, 39, 48, and 50. The exposed aquifers were characterized by water head, which reaches its greatest magnitude at the foot of the slopes. In hydrogeological borehole No. 31 the water column reached 9.70 m, with an absolute elevation of the established level of 180.89 m. In hydrogeological borehole No. 39 the level stood at elevation 183.38.

At springs Nos. 1 and 2, hydrometric observations were made of the discharge and temperature of the water. The results obtained from the observations indicate that the regime of the springs to some extent reflects changes in meteorological conditions. After rains, the discharge of the springs was twice as great as during the drought period.

The formation of deluvial waters must be assumed to occur at the expense of two factors, the quantitative relationship of which has not been established. First, it is promoted by the infiltration of local atmospheric precipitation, as is proved by the dependence of the discharge of the springs on changes in meteorological conditions. Second, apparently, a significant role in the recharge of deluvial waters is played by lateral (side) inflow of groundwater from the bedrock.

c) Alluvial waters.

In the alluvial deposits of the Barzas River and its tributaries (the P. Shurap, Studenaya, and others), in addition to the perched waters noted above, the principal aquifer is widely distributed. It is confined to the sandy-pebble stratum lying at the base of the alluvial formations of the first and second terraces. This aquifer is less developed within the valley of the Yaya River, where the sandy-pebble stratum has a lens-like form. A more detailed manifestation of the pebble aquifer has been clarified for the valley of the Barzas River in the area of the Barzas mine.

Depending on the orography and geological features, the depth of occurrence of the aquifer varies within the range from 3.45 m (hydrogeological borehole No. 46) to 17.15 m (hydrogeological borehole No. 19) and more meters, measured from the ground surface. The exposure of the aquifer was, as a rule, accompanied by a rise of the water level in the boreholes. The depth of occurrence of the pebble aquifer and the magnitude of the head are illustrated by the geological section along line 1—1 (Fig. 3), which shows a regular lowering of the piezometric-surface line in the direction from the slope of the bedrock bank toward the Barzas River, which is explained by drainage of the groundwater by the river. Along the terrace margins, the line of the piezometric surface of the aquifer has an absolute elevation of up to 174.78 m (hydrogeological borehole No. 27), which decreases toward the Barzas River to an elevation of 166.90 m.

From the geological section along line 1—1 it follows that the gravel-bearing aquifer communicates with the aquifers of the deluvium. The latter, extending higher up the slopes, have absolute elevations of the established level of 183.38 m (hydrogeol. borehole No. 39) and more, which considerably exceeds the elevations of the top of the gravel, averaging 165—166 m. The difference between the cited elevations reaches 17—18 m, which represents the magnitude of the excess hydrostatic pressure transmitted from the aquifers of the deluvium to the gravel-bearing aquifer. This circumstance, together with the covering of the gravel-bearing aquifer by weakly permeable clays and loams, determines the confined character of the horizon under consideration.

Long-term observations of fluctuations in the level and temperature of the groundwater were not carried out. Comparatively prolonged observations were made at hydrogeol. borehole No. 23, where the water level fluctuated from a minimum of 6.45 m¹) (3.7.35) to a maximum of 4.90 (3.10.35), with an amplitude between these values of 1.55 m. Generally speaking, the water level in wells located in different parts of the valley of the Barzas River fluctuated to unequal degrees. In workings situated near the Barzas River, the influence of groundwater backwater from the river was observed. With a 2 m rise of the water horizon in the Barzas River, the level in pit No. 1 bis rose by 1 m (23.10.35). Meanwhile, in hydrogeol. borehole No. 30, laid down on the margin of the floodplain, the indicated backwater was not observed.

During the period of observations of the temperature of the groundwater (from 11.2 to 22.1—35), it was established that the latter fluctuated from 2 (8.4) to 10° (3.7.35).

The water abundance of the gravel-bearing aquifer, determined in different parts of the valley of the Barzas River, is characterized by small values. The greatest specific yield—1.25 l/sec.²) was found in core-drilling borehole No. 104, and the smallest was observed in hydrogeol. borehole No. 37, reaching 0.13 l/sec. (see Table 2).

The increased specific yield (2 l/sec.) in borehole No. 104 is explained by additional filtration of water from a lake located near this borehole and communicating through the gravel with the groundwater.

We shall not dwell here on the magnitude of the maximum inflow of water from the aquifer into the workings, which is of decisive importance in the matter of mine construction at the Barzas deposit. We shall consider this question below.

Let us dwell on the interrelations of the perched waters with the aquifer in the gravel. For the portion of the floodplain of the Barzas River, the lower

¹) From the mouth of the borehole.
²) By specific yield is meant the amount of water inflow per unit time, when the water level is lowered by 1 m.

Table 2.

Hydrogeological data for groundwater confined to the pebble bed of the Barzas River valley

the boundary of the perched waters more often merges with the zone of water saturation through capillary rise and the pressure of water from below upward, caused by the head of water from the underlying aquifer. But in individual sectors, as was revealed by the passage of pit No. 1 bis, the lower boundary of the perched water is located at the contact of loess-like loam with blue silty clay.

This clay, being a weakly permeable soil, isolates the perched water from communication with the waters of the pebble bed.

The sources of recharge of the pebble-bed aquifer have also been more or less clarified. Guided by the geological structure (Fig. 3), the main recharge of the pebble-bed aquifer may be attributed to deluvial waters, which enter along the sides of the Barzas River valley. Evidently, a certain role in recharging the pebble-bed aquifer is also played by lateral (side) inflow of groundwater from the bedrock.

Next, let us see whether the recharge of this aquifer is not due to the surface waters of the Barzas River? The latter cannot feed this horizon, since its highest water level¹⁾ (abs. elev. 166,61 m) lies below the piezometric level of the groundwater (174,78 m—hydrogeological well No. 27) and, as was noted earlier, on the contrary, the Barzas River drains the groundwater, which partly explains the increase in water discharge in the river by 1,75 m³/sec along the reach of its course from hydrometric station No. 1 to station No. 2 (Fig. 2).

¹⁾ At hydrometric station No. 2.

2. Stratal-fissure waters of argillites, sandstones, and other rocks of the Balakhon suite of the Lower Carboniferous.

The water-bearing capacity of the Balakhon and Ostrog suites can be characterized only on the basis of materials collected during geological mapping of the area. In the northern part of the Barzas district the Balakhon suite showed no appreciable water-bearing capacity. This suite possesses slight water-bearing capacity within the valley of the Levaya Konokhta River. Here, somewhat below the settlement of Nizhne-Konokhtinsky, spring No. 57 was recorded; its waters issue from fissures in argillites and sandstones with a discharge of up to 0.1 l/sec. Along the river valley above and below this spring, a number of other, smaller springs are manifested.

3. Fissure-karst waters of Lower Carboniferous limestones.

The most water-bearing formations of the district should be considered the Lower Carboniferous limestones. This observed situation is confirmed by the abundance of spring outlets associated with the area of distribution of this formation. The latter includes the Perfilshino, Verkhotomsk, and Balakhon limestones, which have a light-gray or dark-gray color, a lumpy structure, fissuring, and signs of karst phenomena. Fissuring and karst forms in the limestones create favorable conditions for the accumulation and circulation of fissure-karst waters. Springs of these waters have been encountered in large numbers in the 4th ravine of the territory of the Nevsky settlement (springs Nos. 36, 38, 39, 40, etc.), where they are developed in the Balakhon limestones with a discharge of up to 1.2 l/sec (spring No. 39). The springs of the 4th ravine have a derivative character of water outflow. Directly from the bedrock—Verkhotomsk limestones—issues spring No. 46, with a discharge of 0.5 l/sec. In the lower reaches of the Petrushina and Stolbovaya rivers, also within the area of distribution of the Balakhon limestones, an abundance of springs has been encountered, some of which yield a water flow of up to 1 l/sec. The largest of them is derivative spring No. 51, which has a summer discharge of up to 2 l/sec and was encountered in the Balakhon limestones.

4. Stratal-fissure waters of conglomerates, sandstones, and argillites of the Lower Carboniferous and Upper Devonian.

The hard, almost massive, porcelain-like sandstones of the Lower Carboniferous and the upper red-colored sequence (sandstones, argillites, and others) of the Upper Devonian have weak water-bearing capacity. Within the area of development of these rocks, springs with a negligible discharge appear, which cannot be measured.

5. Fissure-karst waters of the Upper Devonian limestones.

The Upper Devonian limestones (Prelongus, Monstrovy, and Falen horizons) have a very heterogeneous structure and are often interbedded with layers of pelitic and psammitic material, as has been proved by deep core drilling on the anticline near the settlement of Nevsky (boreholes Nos. 112 and 116). The presence of pelitic material, which impedes the intensive development of karst forms in the limestones, accounts for the low water-bearing capacity of the latter. They are characterized by a significantly lower water-bearing capacity than the Lower Carboniferous limestones.

Within the area of the Upper Devonian deposits only two characteristic springs have been recorded (springs Nos. 30 and 56); of these, spring No. 30 has derivative outlets, while spring No. 56 has primary outlets. The latter is located at the foot of the right primary bank of the Barzas River, is associated with fractures in the rocks of the Prelongus horizon, and yields an ascending discharge of water with gas emission ($\mathrm{CO_2}$, N and O). The discharge of these springs was measured at values up to 0.42 l/sec (spring No. 30). The springs of the limestone formations also include the springs of the 1st and 2nd districts of the Barzas mine. Their significantly decreasing discharge during the period of summer droughts indicates atmospheric replenishment of the waters of these springs.

In the opinion of A. V. Tyzhnov and G. G. Popov (7), who carried out observations in borehole No. 116, the Prelongus and Monstrovy beds are the more water-bearing among the Upper Devonian rocks.

We can judge the water-bearing capacity of the middle red-colored sequence of the Upper Devonian only from a single object of observation. This sequence, composed of argillites, sandstones, and conglomerates, contains fissure-stratal waters. They were recorded by A. V. Tyzhnov and G. G. Popov (7) in test pit No. 8, which penetrated kaolinized sandstones and argillites. A slight inflow of water appeared here at a depth of 9–10 m, in the eluvium of the bedrock. At a depth of 14.0–14.5 m the inflow of water increased noticeably, and at a depth of 14.9 m, when the water-bearing brownish-red sandstone was opened, the test pit had to be stopped because of the large inflow of water.

6. Stratal-fissure waters of conglomerates, sandstones, limestones, and other rocks of the Middle and Lower Devonian.

The hydrogeological features of the Middle and Lower Devonian sequences can be characterized from the springs that have been identified and from coal core-drilling data. Springs of these waters, issuing directly from the bedrock, were encountered along the Trudnaya, Sergeevka, and Chernaya rivers and on the southern slope of Krasnaya Gora (springs Nos. 52, 53, 54, and 55), with a discharge of up to 0.3 l/sec. The greatest discharge, reaching up to 1.12 l/sec, was observed in derivative spring No. 8, whose waters issue from blocks and rubble of conglomerates and sandstones.

The occurrence of these waters has been studied in greatest detail within the Barzas mine, where a large amount of core drilling was carried out. The results of the drilling are as follows.

The rocks of the productive Devonian series are composed of alternating beds of conglomerates, sandstones, limestones, and argillites with seams of sapromyxite coals, which are cut by a system of large and small tectonic fractures and joints. In addition, the rocks, more often having a calcareous-clayey cement, are characterized by low strength and considerable porosity (sandstones, coals, etc.). The alternation of permeable beds (conglomerates and sandstones) with impermeable argillites, together with the general tectonics of the Barzas mine area (the dip of the rocks to the west at an angle of 15–35°) and the position of the groundwater recharge area at elevated hypsometric levels on the right bank of the Barzas River, determine the characteristics of these waters, which are distinguished by a high head, reaching its greatest value in the valley of the Barzas River. In places, the head exceeds the ground surface by several meters and causes many boreholes to flow artesian (boreholes Nos. 85, 99, 101, 109, 110, and others).

It should be noted that, owing to the considerable number of various fractures in the rocks, on the one hand, and insufficiently thorough hydrogeological documentation during drilling, on the other, it is at present difficult to distinguish individual water-bearing horizons of the pressure waters. Nevertheless, analysis of the available material from hydrogeological observations of 1934 and 1935, carried out in the areas of the 2nd and 3rd mine fields, shows that the self-flowing waters are confined to certain beds of the geological section. Thus, for example, in many coal boreholes (Nos. 89, 90, 99, 102, 112, and others), the self-discharge of water was usually associated with the opening of beds of conglomerates and sandstones. No less characteristic beds yielding pressure waters are the seams of sapromyxite coals (boreholes Nos. 99 and 102). The magnitude of the groundwater head is measured by a water column of up to 205 m (borehole No. 99). The greatest (recorded) excess of the water head above the ground surface occurred in borehole No. 102, reaching +6.55 m. The water head increases as the borehole opens deeper water-bearing horizons.

Comparing the absolute elevations of the water level in the core boreholes, we arrive at the conclusion that the general lowering of the piezometric surface of the pressure waters is from east to west, i.e., from the side of the right bedrock bank of the Barzas River toward the thalweg of the latter’s valley. The piezometers in boreholes over a distance of 800 m decrease from 200 m absolute elevation (borehole No. 96) to 180 m (borehole No. 93), i.e., by 20 m, which gives a gradient of 0.025.

The temperature of the waters under consideration changed little over the observation period in Barzas Mine I, varying from 3.5° (10.3.35) to 7.4° (31.8.35).

Observations of the water abundance of the groundwater horizons were carried out in boreholes and in Mine I. Comparatively long observations (from 22.7 to 7.10.1935) of water inflow were made in borehole No. 99 (diam. 75 mm), where, when the level was lowered by 2 m, the water inflow varied from 0.1 to 0.15 l/sec.

The specific yield, summing the inflows of water from aquifer horizons not isolated from one another, fluctuated within considerable limits. It reached its greatest value in borehole No. 109 (diam. 95 mm) and was equal to 2 l/sec; the smallest was in borehole No. 90 (diam. 95 mm), amounting to 0.1 l/sec.

An increased specific yield, equal to 2 l/sec, occurred when strongly fissured limestone was opened in the interval 23.18–47.26 m from the mouth of borehole No. 109.

According to the available data on the self-discharge of water from boreholes, an approximately linear relationship is observed between the lowering of the level ($S$) and the increase in discharge ($Q$), as shown in Table 3.

Table 3.

Dependence of discharge on lowering of the level for confined waters

In Mine I the maximum inflow from individual aquifer horizons enclosed in conglomerates reached 11 l/sec, which was established during water pumping.

The total inflow of groundwater into the mine was characterized by variability. During the sinking of the shaft of Mine I it reached 13 l/sec (June 1932), which by 1934–1935 had decreased to an average value of 6 l/sec. The general water abundance of fissure-stratal waters depends on meteorological conditions, as is evidenced by the annual observations of 1935 of the total inflow of water in the development workings of Mine I. From the materials of these observations it follows that the minimum inflows (4.8–5 l/sec) of water in the mine workings occur in February–March, and the maximum inflows (8–9 l/sec) fall in mid-May and the second half of June. In May the maximum water inflow arises from infiltration of spring rains and, partly, spring meltwater; in June it is formed during the fall of abundant

atmospheric precipitation. Sharp seasonal fluctuations in the discharge of Devonian waters are characteristic only of the shallow horizons exposed by shaft I, deepened to 60 m. In borehole No. 99, which exposed the water-bearing horizons at a depth of 150–200 m, the inflow of water more smoothly reflects its dependence on changes in meteorological conditions, varying from 0.1 to 0.15 l/sec. On the basis of these considerations, the principal replenishment of fissure-stratal waters takes place at the expense of atmospheric precipitation falling within the recharge area of the former. As follows from the geological structure and topographic conditions of the region, the main recharge area of the Devonian waters is confined to the right bank of the Barzas River. Here the most favorable areas for the infiltration of atmospheric precipitation into the depths should be considered the upper reaches of deep valleys and ravines, where the weathered Devonian rocks in places crop out directly at the surface or are covered by a loess-like mantle of insignificant thickness (see geomorphology). The elevated hypsometric position of the recharge area, the alternation of permeable beds with impermeable ones, and the general westward dip of the rocks determine the confined character of the Devonian waters. A partial increase in the head of the waters may be caused by the pressure of gases accumulating in the water-bearing beds. The presence of gases has been found in many boreholes deepened into the Devonian rocks (boreholes Nos. 85, 99, 110, etc.).

7. Fissure waters of diabases, porphyrites, and other rocks of the Lower Devonian and Cambro-Silurian.

The erupted rocks of the Lower Devonian (diabases, porphyrites, and others) and the pre-Devonian formations (shales, conglomerates, and microquartzites), in terms of their degree of water-bearing capacity, must be placed second after the Lower Carboniferous limestones. The noted rocks, possessing fissuring, contain fissure waters.

In the area of development of erupted rocks (right bank of the Barzas River), many springs have been encountered. The latter have been found in large numbers along the valleys of the Vasil’evka and Dedushkina streams. Characteristic discharges of fissure waters onto the ground surface are springs Nos. 4 and 21, where the water appears as concentrated jets from fissures in the bedrock. The first of them is confined to porphyrites, the second—to diabases.

A series of other springs—Nos. 5, 9, 10, 11, 20, and 22, recorded within the area of distribution of erupted rocks, appear on the ground surface through a deluvial cover. The discharges of the springs ranged from 0.015 (spring No. 9) to 1.6 l/sec (spring No. 5).

Stationary hydrometric observations carried out at spring No. 4 prove that the discharge and temperature of the water of the spring-

...spring depend on meteorological factors. In summer, when there was no rain, the discharge of the spring averaged 0.25 l/sec and the water temperature was 4.5°. In rainy August the discharge reached up to 0.4 l/sec and the temperature 5°. In dry weather in October and early November the discharge of spring No. 4 was 0.25 l/sec and the water temperature 4.5°. These observations and other data make it possible to say that the fissure waters are formed at the expense of local atmospheric precipitation.

The area of accumulation of the waters of the erupted Devonian and Cambro-Silurian rocks extends over the vast spaces of the ancient peneplain (watershed) situated between the Barzas River and the Tuganakovsky Kelbes River. The atmospheric precipitation falling here, depending on the tectonics and the slope of the locality, apparently forms two fronts of groundwater; one of them is directed toward the Barzas River, the other toward the Kelbes River, and the latter water front we exclude from consideration because of the lack of the necessary information.

The formation of fissure waters of the Cambro-Silurian rocks directed toward the Barzas proceeds in the same way as in the case of the Devonian waters considered above. The identified areas of recharge of the Cambro-Silurian fissure waters should include the area of Krasnaya Gora with outcrops of weathered bedrock and the upper reaches of valleys and ravines (the Omutnaya River, etc.), along which coarse fragments of rocks are encountered, capable of absorbing atmospheric precipitation and also carrying the latter deep into the rocks.

Water Quality

Water samples for chemical analysis were taken in the rivers and according to the distinguished types of underground waters, excluding waters of the second and fourth types. Waters of the Middle and Lower Devonian were subjected to more detailed investigation.

The data of chemical analysis are given in Table 4.

1. Surface waters (the Barzas River, 2nd spring, etc.) are weakly mineralized. The dry residue in the water does not exceed 272.4 mg/l, and the total hardness is 13.61 German degrees. Among the salts in the water, carbonates predominate, and a fairly large percentage falls to weak acids (HCO₃). Surface waters belong to Palmer’s alkaline waters of class 1.

2. Groundwaters are characterized by somewhat greater mineralization than surface waters. They give a dry residue from 258.3 to 436.0 mg/l, in accordance with which the total hardness is expressed from 9.64 German degrees (hydrogeol. borehole No. 37) to 22.9 German degrees (hydrogeol. borehole No. 12); carbonate salts predominate in the water, and chlorides and sulfates occur in insignificant quantities. Of the acid anions, the water contains much HCO₃ (50 percent-equivalent composition). According to Palmer’s classification, the groundwaters belong to soft alkaline waters of class 1.

Table 4

Data of chemical analyses of surface and ground waters

Note. Water analyses Nos. 1 through 4 were carried out by the Kemerovo chemical laboratories.

1. Waters of the Lower Carboniferous limestones differ from the other waters of the region by a comparatively high mineralization (dry residue 314 mg/l) and a high total hardness, which equals 16.59 German degrees (spring No. 37). The total hardness, formed by the high content of calcium and magnesium ions in the water, consists mainly of carbonate hardness (13.41–13.59 German degrees), while the share of permanent hardness accounts for an insignificant value (1.6–3.0 German degrees). The large quantity of calcium and magnesium ions, comprising up to 43.58 percent-equivalents of the composition (spring No. 37), fully corresponds to the medium of distribution of waters circulating in the area of limestone development. On reaching the surface, the waters of the limestones deposit travertine (springs Nos. 37, 38, and others). Anions of weak acids (\(\mathrm{HCO}_3\)) occur in the water up to 36.89–43.66%, which, in combination with the cations of alkaline-earth metals, give a considerable value of the second alkalinity (72.78–87.32%).

2. Waters of the Upper Devonian limestones have been sampled to an insufficient degree. Judging by the water of spring No. 30, which issues from the Frasnian limestone, the chemical composition of these waters fits entirely within the framework of the waters of the Lower Carboniferous limestones. Here attention is deserved by the highly mineralized water taken from borehole No. 112 at the latter’s depth of 380 m. This water, apparently, is associated with the Frasnian horizon of the limestones. It is distinguished by a dry residue of up to 5308 mg/l and a high content of \(\mathrm{Na} + \mathrm{K}\) (1441 mg/l) and \(\mathrm{SO}_4\) (3009 mg/l). The nature of this water has remained unexplained.

3. Waters of the Middle and Lower Devonian, investigated at various depths, have a considerably variable chemical composition.

In the surface layers (spring No. 8) they possess weak mineralization (dry residue 189.0 mg/l), low hardness (6.53 German degrees), and a high content of weak acids, in which they are partly analogous to the groundwaters of the loose stratum.

At deeper horizons (depth 50–100 m), the waters under consideration acquire greater mineralization (dry residue 222–323.5 mg/l) and increased total hardness—10.05–10.64 German degrees (mine I and borehole No. 99).

From still deeper horizons (depth 150–200 m), both the physical properties and the chemical composition of the waters change sharply. The changes are expressed in a decrease in the content of calcium + magnesium in the water and, conversely, in an increase of sodium and potassium to 31.38%. The anions of strong acids begin to predominate significantly over those of weak acids. In this connection the water no longer belongs to the alkaline waters, as was the case in the upper horizons, but to hard waters (class III), in which the dominant importance is held by the first (63.56%) and second (21.72%) salinities, with an insignificant second alkalinity (14.72%).

In addition, groundwaters from great depths are often saturated with various gases dissolved in the water. There are a number

columnar flowing wells Nos. 1, 85, 99, 110, and 112, in which gas evolution was observed. Water taken from well No. 99 contains hydrogen sulfide in an amount of 1.94 mg/l. In the waters of other wells, hydrogen sulfide occurs in smaller quantities. The chemical analysis of the gases taken from the wells is expressed by the following data, given in Table 5.

Table 5.

Results of chemical analyses of gases

It is evident from the table that the gases are represented mainly by saturated hydrocarbons \((C_nH_{2n+2})\), nitrogen, and a small quantity of rare gases.

6. Waters of igneous rocks of the Devonian and pre-Devonian formations (springs Nos. 4 and 35) differ from the waters of other rocks by insignificant mineralization (dry residue, 135.1—185.5 mg/l) and low total hardness (5.23—5.52 German degrees). In the water of spring No. 4 there is observed a high content of anions of strong acids (41.42%), which, in combination with the cations of sodium, potassium, and magnesium, forms appreciable values of primary and secondary salinities.

From consideration of the physicochemical features of the surface and underground waters of the area, the following conclusions may be drawn.

First, the surface and underground waters are, to one degree or another, suitable for drinking purposes. The most suitable are the fissure waters of igneous rocks, since the dry residue in them reaches no more than 185.5 mg/l.

Second, as deeper horizons are opened up, the mineralization of the Devonian waters increases (wells Nos. 99 and 112).

Third, the change in the chemical composition of the Devonian waters with depth and the presence of gases in them are not yet sufficient indicators of the oil-bearing capacity of the Barzas district. The gases (methane,

carbon dioxide and hydrogen sulfide), present in the deep horizons of the Devonian, may be a product formed both under the conditions of coal deposits and of oil deposits. For a final judgment on the reasons for the content in the water of heavy hydrocarbons (ethane, butane, etc.), which are the usual companions of oil, we do not have a sufficient number of physicochemical analyses of waters.

Questions of Mine Construction.

1. Characteristics of the investigations carried out.

The direction and program of engineering-hydrogeological investigations for mine construction in the district were outlined in 1934 (2). This complex of investigations was not fully completed by the work of 1934 and 1935. The unfinished part is the determination of the amount of water inflow during the sinking of the mine shaft within the limits of the floodplain.

Of the work carried out in 1934, we note the determination of the filtration coefficient of the gravel and of the maximum inflow of water from the gravel aquifer. For this purpose, exploratory hydrogeological work was carried out within the valley of the Barzas River, and experimental water pumpings were made by the Timov method on an experimental group (hydrogeological borehole No. 12). Pumpings of water on the group, located on the floodplain of the Barzas River, were carried out with three drawdowns of the water level by 1.25 and 3.5 m from its initial position.

The filtration coefficient of the gravel ($K$), calculated for the three indicated drawdowns by the Tima-Dupuit formula—

\[ K=\left(\frac{g(\lg x_2-\lg x_1)}{2.73\,as}\right), \]

is on average equal to 0.0003–0.0004 m/sec (2).

This value of “$K$” is somewhat small for gravel in general, but, taking into account that the Barzas gravel is very strongly silted, it must be considered quite normal.

The maximum yield of borehole No. 12, which exposed the gravel aquifer, was 1.25 l/sec.

In 1935, work was carried out to determine the filtration properties of the eluvium lying beneath the alluvial sediments, and to determine the maximum inflow of water from the gravel aquifer.

The filtration properties of the eluvium were studied in the state of natural moisture. In almost all boreholes the eluvium was very moist or even wet. In addition, isolation of the gravel aquifer by driving the shoe of the casing pipes into the eluvium (2–5 m below the bottom of the gravel) was not successful, and 12–24 hours after this operation in the bore-

water appeared in them, the level of which rose to the elevation of the standing water level from the pebble aquifer (hydrogeol. borehole No. 35, etc.). On the basis of the experiments and observations carried out, it may be said that the eluvium is a weakly water-permeable soil. The thickness and character of occurrence of the eluvium beneath the valley of the Barzas River are illustrated in Fig. 3.

In order to determine the maximum inflow of water from the pebble aquifer within the floodplain of the Barzas River, test pit No. 1-bis was sunk. During the sinking of the test pit, mechanical drainage was used, consisting of a California horizontal pump No. 20, whose maximum capacity (at 85 piston strokes) reached 5 l/sec.

The inflow of water at the roof of the pebble bed (lowering of the level by 2.16 m) reached 2.04 l/sec. When the level was lowered by 2.46 m, that is, by 0.20 m below the roof of the pebble bed, the inflow was equal to 4 l/sec. With greater lowerings of the level (down to 3.16 m), the magnitude of the inflow—4 l/sec—remained constant, and this is what we take as the maximum inflow of water into the test pit from the pebble aquifer.

If one also takes into account that the test pit is located in a bend of the Barzas River (see Fig. 2), where filtration of water from the river could have occurred, the inflow of 4 l/sec must be regarded as somewhat exaggerated.

The sinking of the test pit also showed that the loess-like soils in the zone of development of perched water poorly maintained vertical walls. When left for a long time in an unsupported state, they collapsed. The water-bearing soils (the sandy-pebble strata) were characterized by very strong running. Running was combated by supporting the walls of the excavation with sheet piling, sinking it 0.5–1 m below the bottom, which gave positive results.

Because of a number of technical difficulties, exploratory drilling for coal did not make it possible to determine the maximum inflows of water from the aquifers of the productive Devonian series. To clarify the latter, in 1935 the sinking of a special hydrogeological borehole beneath the shaft of Mine II was planned. But Kemerovokombinatstroy did not allocate funds for sinking the borehole because of uncertainty regarding the location of the mine.

In view of the circumstances noted, we shall approach the determination of maximum inflows from the Devonian aquifers theoretically, using for this purpose data from pumping water from core boreholes Nos. 99 and 101. The first of them is located on the second terrace of the Barzas River, the second—on the floodplain.

In these boreholes, experimental pumpings of water were carried out with a lowering of the level by 1 and 2 m. Having two established lowerings and discharges, and using the data of G. Keller (3), we determined the dependence of the discharge of the boreholes on greater lowerings. In borehole No. 99 the aquifer enclosed in the coal is characterized by a maximum inflow of 9 l/sec. In borehole ...

No. 101, the aquifer confined to the sandstone has a yield of 8 l/sec.

The cited values of yield cannot claim great accuracy and show only the order of magnitude of the inflow; nevertheless, they are suitable for approximate calculations.

2. The possibility of carrying out mining-development work within the valley of the Barzas River.

Having become acquainted with the geological and hydrogeological conditions of the district, let us proceed to consider questions of shaft construction at the Barzas mine.

The principal questions of construction are—the possibility of sinking the mine shaft within the valley of the Barzas River and the possibility of exploiting deposits beneath it. Let us consider these questions.

a) Sinking a mine shaft within the valley of the Barzas River.

As was already said above, the exact location of the projected shaft of mine II has not yet been established. There are two variants, one of which provides for laying the mine shaft in the second mine field, the other—in the third field.

Because of this uncertainty, in what follows we shall consider the most difficult conditions for sinking the mine shaft on the floodplain of the third mine field.

In the process of sinking the shaft, two stages must be provided for. The first stage is the sinking of the loose stratum; the second is the sinking of the bedrock.

First stage. According to the actual materials of the investigations, the difficulties of the first stage consist in overcoming flowing, generally unstable, soils and the inflow of water from the pebble aquifer.

From observations during the sinking of test pit No. 1-bis it is known that loess-like loams collapsed and the water-bearing soils flowed. Soil flow must be regarded as the more dangerous phenomenon. It can be combated by supporting the walls of the working with driven sheet-pile timbering below the face, as was practiced and gave positive results in the sinking of test pit No. 1-bis.

The inflow of water from the pebble aquifer will not present special difficulties. In test pit No. 1-bis, which had a cross-section of \(1.9 \times 1.9\) m, the maximum inflow reached 4 l/sec. But this is true for a working with a cross-section of \(1.9 \times 1.9\) m, whereas with a mine cross-section of \(3.00 \times 5.00\) the inflow of water will be expressed by a somewhat larger figure. To determine it, let us resort to the following calculations. First we shall determine the diameters of the test pit and the mine. The diameter of the test pit (by the formula \(2 \times a^{1)} \times 0.636\))

\(^{1)}\) where \(a\) is the side of the square.

is equal to 1.4 m. We convert the shaft section \(5.0 \times 3.0\) m into an equal-area square, whose side is \(\sqrt{15}=3.87\) m; then the shaft diameter \((3.87 \times 2 \times 0.636)\) will be expressed as 4.9 m.

According to the diagram given by A. A. Krasnopolsky (4, p. 81), an increase in the diameter of the well from 1.4 m to 4.9 m causes an increase in discharge by approximately 1.33 times. From this regularity it follows that, if instead of a borehole the shaft is sunk, the inflow of water into the latter, as compared with the former, will be 1.33 times greater, namely \(4 \times 1.33 = 5.32\) l/sec. Taking into account a certain inflow from the perched-water side, the inflow into the shaft should be taken as 6 l/sec.

Bearing in mind that, in calculating the maximum inflow of water into the shaft, we were guided by the inflow into a borehole located in the bend of the Barzas River, where filtration of water from the river could have had an effect, the calculated inflow into the shaft is somewhat exaggerated and, evidently, if the shaft is sunk far from the Barzas River it will be somewhat smaller.

Such are the conditions for driving the shaft in the alluvial deposits of the floodplain. At a depth of 8–10 m the gravel will end, and the face of the shaft will deepen into the products of weathering of the bedrock (eluvium), represented more often by weakly permeable clays (Fig. 3). Therefore, subsequently, with isolation (by the concreting method) of the groundwaters of the gravel, a very small quantity of water will enter the shaft. However, if the eluvium is represented by products of weathering of sandstones or conglomerates, which are permeable, then below the bottom of the gravel, waters of the gravel aquifer and waters of the Devonian rocks will seep into the shaft.

Second stage. Driving the shaft in the bedrock will likewise not present particular difficulties. All the more so since, in this respect, there is sufficient experience from the driving of shaft I. But, proceeding from the history of its driving and from hydrogeological observations in core-drilling boreholes, we must take into account the possibility of encountering underground pressure waters, breakthroughs of these waters, and the possibility of flooding of the shaft. Breakthroughs of water may occur when beds of conglomerate, coarse-grained sandstones, and beds of sapromixite coals are encountered. In this connection we note that, if during the driving of shaft I the head of the groundwater did not reach the earth’s surface, then under the conditions of the valley it may be situated up to 6.55 m (borehole No. 101) and above this surface.

The question of the amount of water inflow into the shaft from the bedrock is resolved on the basis of theoretical calculations. Here we shall consider two variants of shaft driving, i.e., on the second terrace of the Barzas River and on the floodplain, taking as a basis the available data for boreholes Nos. 99 and 101.

Variant on the second terrace (2nd shaft field). The maximum value of the inflow of water into borehole No. 99 is determined as 9 l/sec,

which is correct for a working with a diameter of 75 mm. With a shaft diameter of 4.9 m the inflow of water will increase. According to the table of Ch. S. Slichter (5, p. 112), in passing from a diameter of 75 mm to 4.9 m the inflow per well must be multiplied by the coefficient 2.4. Then the inflow of water into the mine shaft will be expressed by the value \(9\ \text{l/sec} \times 2.4 = 21.6\ \text{l/sec}\). This corresponds to the inflow of water from one aquifer horizon situated at the average depths of the mine. At a mine depth of up to 200 m, approximately three aquifer horizons with the indicated yield may be encountered. Therefore the inflow of water in the bedrock from three aquifer horizons will be expressed by the value \(21.6 \times 3 = 64.8\ \text{l/sec}\).

Hence the total inflow of water into the mine shaft, taking into account the inflow from the pebble aquifer horizon determined in prospecting pit No. 1-bis and equal to 6 l/sec, will be expressed by the value \(64.8 + 6 = 70.8\), or, rounded off, 71 l/sec.

Variant on the floodplain (3rd mine field). The maximum inflow of water in borehole No. 101 with a diameter of 85 mm reaches 8 l/sec. With a mine-shaft diameter of 4.9 m it will reach \(8 \times 2.2 = 17.6\ \text{l/sec}\). Under the conditions of the 3rd mine field one must also expect approximately three aquifer horizons with a yield of up to 17.6 l/sec. Then the inflow from three aquifer horizons will be equal to \(17.6 \times 3 = 52.8\ \text{l/sec}\), or, rounded off, 53 l/sec. Adding 53 l/sec to the inflow of water from the pebble aquifer horizon—6 l/sec—we obtain the total inflow of water along the mine shaft, equal to 59 l/sec.

Comparing the two variants for locating the mine shaft, one cannot pass over in silence the question of the stability of the soils for the surface structures above the shaft. The soils in the floodplain area, owing to the presence in them of perched water causing waterlogging, will be less suitable as foundations for the surface structures above the shaft than those on the second terrace, where they are almost devoid of perched water and waterlogging.

b) Possibility of exploiting the coal deposits beneath the valley of the Barzas River.

The main accumulations of sapromixite coals of the Barzas mine, counting the 2nd and 3rd mine fields, are concentrated in the valley of the Barzas River. If the absolute elevation of the bottom of the valley of this river (the upper boundary of the alluvium) is taken on average as 160 m and compared with the contour lines of the main sapromixite seam, it follows from this that approximately 80–90% of the coal reserves lie below the bottom of the river valley. At the same time, west of mine I, that is, between hydrogeological boreholes Nos. 35 and 26, the outcrop of the sapromixite seam to the daylight surface is cut as many as three times by the channel of the Barzas River. Consequently, the hydrogeological situation for coal exploitation is not entirely favorable. The unfavorable character is due to the possibility of filtration of waters into the mine workings from the Barzas River, oxbow lakes, lakes, and the groundwater of the pebble deposit, both directly through the coal seam and through water-bearing

...the overlying beds and, finally, it apparently will also occur along tectonic fissures.

In this connection, let us consider the possibility of filtration of the waters noted and the danger of the mine workings being flooded by these waters.

The filtration of water into a working from the pebble-bearing aquifer will not be of threatening magnitude, as is proved by the insignificant filtration coefficient of the pebbles (0.0003–0.0004 m/sec) and by the weak filtration properties of the eluvium lying beneath the pebbles.

The greatest amount of filtration, actually dangerous with respect to flooding of the workings, may occur from the Barzas River, especially in those sections where the river repeatedly cuts the outcrop of the sapromixite seam. In order to eliminate this danger, precautionary measures will have to be carried out. One such measure should be considered the straightening of the channel of the Barzas River. It is expedient to carry this out along the line of hydrogeological boreholes Nos. 34 and 45, thereby eliminating the possibility of water filtration through the coal outcrop in the third mine field.

For the southern section of the second mine field, which is north of the mouth of the Dedushkina River, straightening the river channel cannot be carried out under orogeological conditions. But it is not especially required, since here the coal seam is unsuitable for extraction and the latter will be carried out in the central and northern parts of the second field.

The detailed design for straightening the river channel will require the undertaking of hydrogeological and hydraulic-engineering investigations.

Despite the precautionary measures indicated, exploitation of the deposit will have to be carried out by a special system of workings, with a pillar of the upper strata left in place and without disturbing the roof of the coal seam in sections of mine workings situated in especially dangerous places (beneath the channel of the Barzas River). Otherwise, disturbance of the roof will lead to the formation of fissures and “subsidence troughs” on the surface of the earth, through which surface and ground waters may subsequently drain, flooding the mine workings.

Guided by the experience of coal extraction in the Donbas beneath river valleys (1, p. 26), we propose, for discussion, the following system for mining sapromixites at the Barzas mine.

Where the dip angle of the seam exceeds 20° beneath the valley of the Barzas River (the 3rd mine field), coal may be extracted with caving of the roof, beginning at a depth of 30 m and lower, measured vertically; moreover, the 30 m should not include the thickness of loose rocks. Where the dip angle is up to 20° (the 2nd mine field), when collapses are possible, cleaning operations beneath the valley may be carried out only beginning at a depth of 50 m, including in this only the bedrock. It is possible that in this case stowing of the workings will also be required.

Thus the questions of mine construction—such as the sinking of a mine shaft within the valley and the exploitation of the coals beneath it—should basically be considered resolved in a positive sense. But before their practical implementation, it is absolutely necessary to drill special hydrogeological boreholes at the sites of the projected mines, with corresponding testing of the aquifer horizons.

Conclusion.

The Barzas district, situated on the northeastern margin of the Kuznetsk coal basin, possesses considerable reserves of sapromixite coals. Orographically, the district is represented by a low-mountain taiga landscape, descending in a northwestern direction and dissected by a dense network of rivers and ravines. The hydrographic network of the landscape is expressed chiefly by the basin of the Barzas River, which is a right tributary of the Yaya River.

The geological structure of the area studied includes Cambro-Silurian, Devonian, Carboniferous, Tertiary, and Quaternary formations.

A feature of the hydrological regime of the Barzas River is a large spring flood, which is formed by the rapid runoff of meltwater over frozen soil. The greatest flood was observed in 1935, when the water level of the Barzas River rose 6.90 m above the low-water level. During this period the river overflowed its banks and covered the entire floodplain terrace with water.

Among the groundwaters of the district, seven principal types may be distinguished.

1) Groundwaters of loose rocks.
2) Stratified-fissure waters of the sandstones and argillites of the Balakhon suite of the Lower Carboniferous.
3) Fissure-karst waters of the Lower Carboniferous.
4) Stratified-fissure waters of conglomerates and other rocks of the Lower Carboniferous and Upper Devonian.
5) Fissure-karst waters of Upper Devonian limestones.
6) Stratified-fissure waters of conglomerates, sandstones, limestones, and other rocks of the Middle and Lower Devonian.
7) Fissure waters of diabases, porphyrites, and other rocks of the Lower Devonian and Cambro-Silurian.

The occurrence of groundwaters of alluvial deposits and of stratified-fissure waters of the Devonian has been most thoroughly studied within the territory of the Barzas mine.

Alluvial groundwaters are widely distributed in the valley of the Barzas River. Their principal aquifer horizon is confined to the sandy-pebble sequence lying at the base of the terrace deposits, and occurs at a depth from 3.45 to 17.75 m. Bounded above and below by water-resistant rocks, the water-

The water-bearing layer contains confined waters, whose piezometric surface descends from the terrace margins in the direction of the Barzas River, which is explained by the drainage of groundwater by the river. The maximum discharge from the aquifer, determined in prospect pit No. 1 bis, amounted to as much as 4 l/sec.

The bedded-fissure waters of the Middle and Lower Devonian include several confined aquifers represented by beds of conglomerates, sandstones, limestones, and sapromixite coals. In the valley of the Barzas River the water head exceeds the ground surface by several meters and causes many wells to flow (wells Nos. 99, 101, etc.). The greatest excess of the water head above the ground surface (+6.55 m) was recorded in well No. 102. The specific discharge of wells, summing the inflow from aquifers not isolated from one another, fluctuated within wide limits, varying from 0.1 to 2 l/sec. The maximum discharge of individual aquifers enclosed in conglomerates reached 11 l/sec, as established by dewatering during the driving of shaft I. The principal recharge area of the fissure-bedded waters is located at the elevated levels of the right bank of the Barzas River. Favorable areas for the infiltration of atmospheric precipitation into the depths should be considered the upper reaches of deep valleys and ravines, where the weathered Devonian rocks in places either crop out directly at the ground surface or are covered by a loess-like mantle of insignificant thickness. The elevated hypsometric position of the recharge area, the alternation of permeable beds with impermeable ones, and the general dip of the rocks to the west determine the confined character of the Devonian waters. A partial increase in the water head may be caused by the pressure of gases accumulating in the aquifers. The presence of gases has been found in many wells sunk into the Devonian rocks (wells Nos. 85, 99, 110, etc.).

In their physical and chemical properties, the surface and underground waters are, to one degree or another, suitable for water supply. The best for drinking purposes are the fissure waters of the igneous rocks, which have a dry residue of no more than 185.5 mg/l and a total hardness of 5.5 German degrees. The degree of mineralization of the Devonian waters increases as deeper aquifers are opened. In addition, these waters not infrequently contain carbon dioxide, hydrogen sulfide, hydrocarbons, oxygen, nitrogen, and rare gases.

The principal accumulations of sapromixite coals (80–90% of the reserves of the 2nd and 3rd mine fields) are concentrated within the valley of the Barzas River, which is characterized by complex hydrogeological conditions. Confined Devonian groundwaters are widespread in the valley, and the river sometimes flows above the coal seam and sometimes cuts it with its channel. This combination of geological and hydrogeological features creates an unfavorable situation for mine construction at the Barzas mine.

Guided by the analysis of the available material, the unfavorable hydrogeological conditions cannot be considered threatening either for the sinking of the mine shaft within the valley or for the exploitation of the coals beneath it. The sinking of the mine shaft in the valley is entirely possible. It should only be borne in mind that the total inflow of underground waters into the mine shaft may reach approximately 71 l/sec. The situation is considerably more complicated with the exploitation of the coals beneath the valley, since in this case the mine workings will be endangered by flooding from underground waters and from water filtering from the Barzas River. The greatest amount of filtration, which is indeed dangerous with respect to the flooding of workings, may occur from the Barzas River, especially in those sections where the river repeatedly cuts through the outcrop of the sapromyxite bed. But the implementation of precautionary measures for straightening the Barzas River and the application of the system of coal extraction practiced in the Donbass will make it possible to exploit the coals beneath the valley of the indicated river. Thus, the questions of mine construction at the Barzas deposit should be regarded as resolved in a positive sense.

What has been noted above is only the first step toward the study of the hydrogeological conditions of the Barzas district. Further investigations should be oriented in two directions.

First, in connection with the requirements of mine construction at the deposit, it is absolutely necessary to carry out exploratory and experimental work at the sites of the projected mines.

Second, in the deep boreholes drilled for petroleum exploration, systematic hydrogeological examination should be established, making it responsible for the qualitative and quantitative testing of the encountered aquifer horizons. Such a measure will make it possible to clarify the causes of the change in the chemical composition of underground waters with depth and will undoubtedly provide valuable material for elucidating the question of the degree of oil-bearing capacity of the Barzas district, which is of great practical and scientific interest.

LIST OF LITERATURE USED

1. Bezgin, A. M.—Fractures of collapses and their “ability” to conduct waves into mines. Mining Journal, No. 8, 1935.

2. Bolshakov, G. M.—Hydrogeological conditions of the Barzas district of Kuzbass (report on work carried out in 1935). Manuscript. Fonds Department of ZSGT, 1935.

3. Keller, G.—Pressure waters, 1930.

4. Krasnopolsky, A. A.—Groundwater and artesian wells. Mining Journal, vol. II, 1912.

5. Slichter, Ch. S.—Underground waters, 1912.

6. Tyazhov, A. V.—Geological sketch of the Barzas district of the Kuznetsk Basin. Materials on the Geology of Siberia, published by the West-Siberian State University, Tomsk, 1938.

7. Onzhe and G. G. Popov.—Preliminary report of the Barzas geological prospecting party for 1936. Manuscript. Fonds Department of the West-Siberian State University, 1937.

8. Finkelshtein, M. M.—On bauxite rocks at Barzas. Manuscript. Fonds Department of ZSGU, 1933.

9. Shkaranda, A. A. and V. A. Orestov.—Hydrogeological sketch of the middle course of the Barzas River. Manuscript. Fonds Department of ZSGT, 1932.

Fig. 2.

Schematic Hydrogeological Map of the Barzas District of Kuzbass

Compiled by P. M. Bolshakov from data of A. V. Tyazhnov, B. K. Dunaev,
A. A. Shkaraba, and P. M. Bolshakov.

Scale: 1 0 1 2 3 4 5 6 7 8 km

Legend