On the Industrial Use of the Bakchar Iron Ore Deposit

G. E. Bakanov

(Presented by the Scientific and Technical Conference on the Use of Mineral Resources of the Tomsk Economic Region)

During the years of Soviet power, the ore industry of our country, from a backward branch of the industrial economy of prerevolutionary Russia, has been transformed into a powerful branch of the national economy of the Soviet Union, equipped with advanced technology. Before the October Socialist Revolution, almost all the mineral wealth of our country was in the hands of foreign capitalists. Ore deposits were exploited in a predatory manner, and their exploration proceeded extremely slowly. The powerful iron ore deposits of Kustanai Oblast, Krasnoyarsk Krai, the Angara-Ilim region, Southern Yakutia, and many others were unknown in prerevolutionary times. Tomsk Oblast was considered entirely oreless.

Under Soviet power, the raw-material base of ferrous metallurgy has grown immeasurably. In explored reserves of iron, molybdenum, manganese, and chromium, the USSR at present occupies first place in the world. In 1913, the total recorded reserves of iron ore in Russia did not exceed 2 billion t, of which only a little more than 1 billion t had been explored. By 1957, the explored reserves of iron ore in the USSR had increased 34-fold and reached 35.9 billion t. In the very latest years, colossal reserves of iron ore of sedimentary origin have been discovered in Tomsk Oblast. The new iron ore basin, which has received the name West Siberian, is one of the largest in the world. According to preliminary exploration data, its geological reserves amount to more than two hundred billion tons \[4; 8\]. With the discovery of the new iron ore basin, the old legend that there are no metalliferous minerals on the territory of Tomsk Oblast has been completely refuted.

During the years of Soviet power, the scale of work in extracting mineral raw materials for the production of ferrous metals has changed sharply. In 1957, iron ore production in the USSR reached 84.2 million t; it had increased 15.7-fold compared with 1917 and almost 340-fold compared with 1920. The iron ore industry of the USSR, the main raw-material base of ferrous metallurgy, had reached this level of development by the fortieth anniversary of the Great October Socialist Revolution. Still more grandiose rates of growth are planned for its subsequent

time. The control figures for the development of the national economy of the USSR for 1959–1965, approved by the Twenty-First Congress of the CPSU, provide for bringing the extraction of crude iron ore by 1965 up to 230–245 million tons, in order to obtain 150–160 million tons of marketable ore and to ensure the smelting of pig iron in the amount of 65–70 million tons. According to the prospective fifteen-year plan for communist construction in the Soviet Union, announced by Comrade N. S. Khrushchev at the jubilee session of the Supreme Soviet of the USSR devoted to the fortieth anniversary of the Soviet state, it is planned to increase the annual extraction of ore by 3–3.5 times as compared with 1957, bringing it up to 250–300 million tons. It is also planned to expand substantially the production of pig iron and steel.

The control figures of the seven-year plan provide for the accelerated development of the economy of the eastern regions of our country. In the current seven-year period, more than 40% of the total volume of capital investments projected for the entire Soviet Union is allocated to the development of the economy of the East, including the Urals, Siberia, the Far East, Kazakhstan, and Central Asia. In connection with this, the share of the eastern regions in all-Union production of industrial output will increase significantly; in particular, in pig-iron smelting in 1965 it will amount to approximately 44%. There is every reason to suppose that in the next seven-year period the share of the eastern regions in the production of ferrous metals will become still higher.

The grandiose development of ferrous metallurgy being carried out in the USSR in the current seven-year period and planned for the subsequent period makes the task of providing it with a powerful ore base extremely important. In connection with this, the question of the industrial use of the ores of the West Siberian iron-ore basin acquires urgent significance.

Among the deposits of the basin, in terms of the state of its study at the present time, the Bakchar deposit, located in the southeastern part of the West Siberian Lowland, is the most promising industrially. It was discovered in 1957 and lies within the administrative boundaries of Bakchar District, Tomsk Oblast. Its nearest boundary is 200 km from the city of Tomsk along the Tomsk–Kolpashevo motor road.

The Bakchar deposit [4] is represented by extensive, well-persistent in thickness, almost horizontal beds of iron ore occurring at a depth of 150–200 m. The ore, of sedimentary origin, consists of loose and weakly cemented varieties of goethite, hydrogoethite, and glauconite-goethite oolites.

The rocks covering the ore deposits are represented by loose sequences of Quaternary and Tertiary deposits. They consist of interbedding clays, loams, aleurites, and water-saturated sands of various grain sizes. Down to a depth of 35–50 m the rocks consist of Quaternary deposits (clays, loams, sands); below these come Tertiary deposits, represented by interbedding of sands and aleurites. In most cases, directly above the ore deposit (the Bakchar member) lie dense Tertiary clays of the Chegan Formation, with a thickness of 8–32 m (about 12 m near Bakchar). Among the underlying rocks, weakly cemented clayey sandstones, aleurolites, quartz-glauconite sandstones, and sands with interbeds of aleurolites predominate, in places enriched with ferruginous minerals. Because of the insignificant iron content, these sands have as yet no great practical importance.

By the Bakchar party of the WSGU, which is part of the Tomsk complex expedition, the deposit under consideration has been subdivided into two

sector: Western and Eastern [4, 169], located at a distance of about 25 km from one another.

Within the Western sector, which has an area of 147.3 km², an almost horizontal bed of iron ore occurs at a depth of 155.6–176.1 m, averaging 163 m; it has a thickness of 17.1–3.8 m, with its average value being 12.8 m; the thickness of the bed more often varies within the range of 10–16 m. The iron content in the ore, by individual boreholes, varies from 34.7% (borehole No. 6) to 42.2% (borehole No. 14) and, on average, from the results for 17 boreholes amounts to 38.3%. The prospective ore reserves of the Western sector have been determined at 29.44 million t/km² and 4.33 billion t within the entire area [4, 205].

Within the boundaries of the Eastern sector, which has an area of 257.7 km², the conditions of ore occurrence and their quality are less favorable than in the Western region. The thickness of the overlying rocks is 185.8 m (from 171.35 to 197.95), and the average thickness of the bed is 11.05 m (1.75–22.05). The iron content by boreholes ranges from 32.2% (borehole No. 10) to 39.1% (borehole No. 1), averaging, according to data from 18 boreholes, 35.1%. Iron-ore reserves: 25.3 million t/km² and 6.52 billion t for the entire Eastern sector.

The total productive area of the Bakchar deposit is 405 km²; the ore reserves, assigned by geologists on the basis of quite objective indicators to category C₁, have been calculated for the entire deposit in the amount of 10.85 billion t, with an average iron content in the ore of 36.06%.

The ores of the Bakchar deposit contain vanadium pentoxide in the following amounts: Western sector—0.25%, Eastern—0.2%, and for the deposit as a whole—0.22%. This component in the ores of the deposit is a valuable alloying addition.

To give an idea of the size of the Bakchar deposit, we present (Table 1) data for the Angara-Pit basin [5, 14], which until the present time has been considered the largest iron-ore basin in Western Siberia. From these data it is evident that, in iron content, the ores of the Bakchar deposit (especially its Western sector) hardly differ from the ores of the Angara-Pit basin. In terms of ore reserves, however, the Bakchar deposit exceeds all the deposits of the Angara part of Krasnoyarsk Krai by more than four times. At the same time, there are sufficient grounds to suppose that, in their technological properties, the ores of the Bakchar deposit are not inferior to the Angara-Pit ores.

Table 1

Angara-Pit basin

From the foregoing it is evident that, in terms of the content of useful components and in terms of ore reserves, the Bakchar deposit is a unique

Fig. 1. Cross-section and plan of the Bakchar open pit.

Cross-section of the open pit along one of its sides
Scale 1:2000

Legend:

• Marl
• Clays
• Topsoil
• Sand
• Iron ore

Open-pit plan
Scale 1:4000

Labels visible on the plan: Section No. 6; Section No. 1; No. 1; No. 2; No. 3; No. 4; No. 5; No. 7; No. 8; No. 9; No. 10; No. 11; No. 12.

Fig. 2. Placement of dumps during stripping.

Legend:

1. Stripping operations.
2. Section of the pit with roadbed.
3. Hydraulic dump.
4. Section in operation.
5. Upland ditch.
6. Drainage ditch.
7. Motor road.
8. Dump pulp pipeline.

Map labels: St. Bakchar; Iksa River; Galka River; village of Vavilovka; settlement of Rudnichny.

Fig. 3. Scheme of open-pit development of the Bakchar deposit.

Legend:

— contact network
— roads

1. Main water collector.
2. Pumping station.
3. Bunker.
4. Conveyor.
5. Hoist.
6. Local water collectors.
7. Pumps and water pipelines.
8. Rock from stripping the ore roof.

Visible labels on the plan:

• Excavator No. 1
• Excavator No. 2
• Excavator No. 3
• Excavator No. 4
• Transport incline
• [[unclear: “drying”/drainage incline label]]

and, along with the Krasnoyarsk deposits on the Angara, may play an important role in the creation of a powerful metallurgical industry in Western Siberia.

In connection with this, it seems very strange that in the Bakchar district the geological work, carried out at the prospecting stage, was completely suspended in 1958. Meanwhile, the absence of data from detailed exploration, conducted at least on the most promising areas, deprives one of the possibility of correctly resolving questions of developing the deposit, designing ore-processing processes (its beneficiation with metallurgical conversion of the concentrates), and giving a well-founded technical and economic assessment of the Bakchar deposit.

Despite the insufficiency of data on the mining-geological character of the deposit, the Department for the Development of Ore Deposits of TPI has attempted to determine the possible cost of the Bakchar ore. This attempt is of known approximation because, for the case of mining the ore by the open-pit method, it was made. Since in the Bakchar district above the ore bodies there are thick strata (150–200 m) of loose rocks consisting of clays, loams, sands, and aleurites, often saturated with water and still poorly studied, it has so far been difficult to plan underground mining (horizontal layers or panels).

In choosing the site for locating the quarry, two areas were considered: near the village of Bakchar and near the village of Polynyanka.

With respect to stripping ratios referred to tons of ore (allowing for widening of the pit walls), both areas proved almost equivalent (the stripping ratio at the area near the village of Bakchar is 0.099, near the village of Polynyanka, 0.095 m³/t). Preference was given to the area located near the village of Bakchar, where the district center is situated and the ore has a higher iron content (40.3%).

Taking into account the high ore content of the Bakchar deposit, the practically unlimited ore reserves, and the fairly complex mining-geological conditions of its development, it is advisable to extract the ore by the open-pit method here, using large quarries (5–10 million t per year) equipped with the most advanced technical means. In drawing up the design for the Bakchar quarry, it was borne in mind that it would fully supply with ore the needs of one fairly large metallurgical plant, with partial export of ore beyond the region. In connection with this, the annual productivity of the quarry was set at 10 million t of crude ore. The period for developing the quarry field is set at 24 years. The required output of ore mass was designed at 240 million t; the industrial and balance reserves of ore were provided for, respectively, at 234.3 and 254.7 million t. From these conditions the dimensions of the quarry were determined: at the base, 1.9 and 2.9 km; at the surface, 2.36 and 3.36 km. The total depth of the quarry is 178 m, in the footwall, 161 m. The area of the quarry field within the limits of the ore body is 5.5 km²; the area of the quarry at the surface is 7.9 km² (Fig. 1).

The volume of stripping for the quarry as a whole was determined at 1115.6 million m³, or on average 4.6 m³ per one t of ore mass. With a total duration of stripping operations of 28 years, the annual volume of stripping will fluctuate within the limits of 54–16 million m³, averaging about 40 million m³. The lifetime of the quarry, including the stripping period before the start of ore extraction, is calculated at 30 years.

Stripping production is designed to be carried out with floating earth-moving equipment of the 1000–80 type; ore mining, with EKG-4 mechanical shovels with buckets of 5 m³ capacity, suitable for operation also in winter. In carrying out stripping and mining operations,

of the work, it is planned to divide the quarry field into 12 sections. From three sections the overburden rocks go to an external hydraulic dump; from the remaining sections they go into the worked-out space (Fig. 2).

Transportation of ore in the quarry is to be carried out along reinforced-concrete roads by freight trolley trucks. From the quarry, with the aid of a cable-belt conveyor, it will be delivered directly into railway cars with a carrying capacity of 100 t, moved on the surface by a special under-car hauler (Fig. 3).

Cleaning the surface of the ore deposit before ore extraction is planned to be carried out by bulldozers; dewatering, by 14M-12x4 pumps; water lowering, by VAN-7 pumps.

Under the designed method of developing the deposit, the shop cost of Bakchar ore (free-on-car at the edge of the quarry on the surface) was determined at 12.10 rubles per tonne, including mining-capital and stripping operations, 10.52; other costs, including extraction, transportation, and loading into cars, 1.58 rubles/t.

In 1956, the shop cost of iron ore in the Krivoi Rog basin at most mines was within the range of 13.46–21.81; in the Urals, 19.14–31.88; in Gornaya Shoria, 22.32–24.13 rubles/t.

Comparing the data cited, it is not difficult to see that, with respect to ore cost, the Bakchar deposit has considerable advantages over many other iron-ore deposits of the Soviet Union. However, as is known, the cost of ore, taken separately, does not give a complete idea of the economic efficiency of developing a deposit. It does not determine the value, quality, and technological properties of the ore; the labor productivity of miners, the qualitative and quantitative losses of ore in the ground, and the intensity of deposit development are not fully reflected in the ore cost. The value of ore, determined as the total value, at state wholesale prices, of the products of production or useful components obtained from one tonne of ore during its processing, does not depend on the cost of the ore. Therefore ores of different value may have the same cost. Sometimes the extraction of a less valuable ore may cost much more than that of richer ores. Everything depends on the mining-geological and economic conditions of deposit development. Therefore, from the cost of ore one can judge the economic efficiency of development only for those deposits that, in terms of their mining-geological and economic conditions, value, and ore quality, differ little from one another.

In this respect, the cost of the metal obtained from the given ore is of great importance. Specifically, as applied to the conditions of the Bakchar deposit, in order to judge the economic efficiency of its development, it is necessary to know what pig iron from Bakchar ore will cost.

If data are available, the cost of pig iron may be found from the equation [9, 75–80]:

\[ C=\frac{100}{\gamma}(c+f_p+t_p)+\frac{100}{\gamma_m}(f_m+t_k); \tag{1} \]

where \(\gamma\) is the yield of pig iron from ore, %;

\(\gamma_m\) is the yield of pig iron from concentrate, %;

\(c\) is the cost of ore, rubles/t;

\(f_p\) is the cost of processing ore at the beneficiation plant, rubles/t;

$t_p$ — costs of transporting ore to the concentration plant, rub./t;
$f_M$ — cost of the metallurgical processing of concentrates, rub./t;
$t_k$ — costs of transporting the concentrate to the plant, rub./t.

Since \(r = \dfrac{\alpha e \varepsilon}{100\delta}\) and \(r_M = \dfrac{\beta \varepsilon_M}{\delta}\), the cost of metal is

\[ C = \frac{100\delta}{\alpha e \varepsilon}(c + f_p + t_p) + \frac{100\delta}{\beta \varepsilon_M}(f_M + t_k), \tag{2} \]

where \(\alpha\) is the iron content in the ore, %;
\(e\) is the quality recovery in ore mining, %;
\(\varepsilon\) is the extraction of iron from ore into pig iron, %;
\(\varepsilon_M\) is the extraction of iron from concentrate into pig iron, %;
\(\beta\) is the iron content in the concentrate, %;
\(\delta\) is the iron content in pig iron, %.

For a well-founded formulation of the question of the industrial use of the ores of this deposit, and of the creation on its basis of a metallurgical plant in Tomsk Oblast, it is necessary to obtain data by which it would be possible to calculate the cost of pig iron from the ores of the Bakchar deposit. For this purpose it is necessary, in the most promising areas of the deposit (the village of Bakchar, the village of Polynanka), to carry out geological studies at the detailed-exploration stage; to comprehensively study the physico-mechanical and technological properties of the ore; to investigate in detail the enclosing rocks and the hydrogeology of the deposit in the areas being explored; and to identify consumers of the ore and the conditions of its transportation.

The information that will be obtained as a result of such studies will make it possible to approach correctly the solution of the technical and economic problems connected with the industrial development of the very rich Bakchar iron-ore deposit.

It seems to us that research work in the above-mentioned direction should be carried out as quickly as possible (in 1960–1962), so that by the end of the current seven-year plan it would be possible to prepare a design assignment for the construction of a large mining-and-metallurgical combine based on the ores of the Bakchar deposit of the West Siberian iron-ore basin (Tomsk Oblast).

LITERATURE

1. Khrunichev N. S., Forty Years of the Great October Socialist Revolution, “Pravda,” 7.XI.1957.

2. The Ore Industry of the USSR on the 40th Anniversary of the Great October, Mining Journal, No. 12, 1957.

3. Skobnikov M. L., The Iron-Ore Base of the USSR on the Historic Date, Mining Journal, No. 11, 1957.

4. Babin A. A. and Dontsenko A. S., Report of the Bakchar Party on the Results of Field Work in the South-Eastern Part of the West Siberian Iron-Ore Basin in 1957–1958, vol. 1 (Tomsk Complex Expedition, 1959).

5. Medvedkov V. I., The Iron-Ore Base of Krasnoyarsk Krai and the Paths of Its Development, Krasnoyarsk, 1958.

6. Nekrasov N., Development of the Natural Resources of the Eastern Regions of the USSR, Kommunist, No. 6, 1959.

7. Calculation of Underground Iron-Ore Mining at Enterprises of the Ministry of Ferrous Metallurgy for 1956 (published by the Ministry of Ferrous Metallurgy of the USSR).

8. Kalugin A. S., New Data on Iron-Ore Deposits of Western Siberia, Bulletin of the West Siberian Geological Administration, No. 1, publ. TGU, 1957.

9. Gorodetskii P. I., Fundamentals of the Design of Mining Enterprises. Metallurgizdat, 1955.