ANALYSIS OF THE COST OF MAINTAINING HAULAGE WORKINGS IN THE MINES OF THE ANZHERO-SUDZHENSK DISTRICT OF KUZBASS

N. A. FEDOROV

Characteristics of the Seams

The mines of the Anzhero-Sudzhensk district work the seams of the Central series, which occupies the middle stratigraphic position in the section of the Balakhon suite. Seven coal seams of industrial importance are subordinate to this series: Desyatyi, Andreevskii, Dvoinoi, Petrovskii, Tonkii, Sluchainyi, and Koksovyi. The Dvoinoi and Sluchainyi seams have workable thickness only in the northern part of the district. In the southern part the Dvoinoi seam is absent, and the Sluchainyi seam, owing to its variable thickness, is worked selectively.

The characteristics of the seams are given in Table 1.

The dip angles of the seams, as a result of the strongly disturbed nature of the deposit, vary from 10–15 to 60–80°. In the field of the “Andreevskaia II” mine, gentle bedding predominates, while in the fields of mines No. 5–7 and No. 9–15, inclined bedding predominates. The direction of strike of the seams and the distance between them are extremely variable.

All mine fields are complicated by numerous disturbances, both with displacement and without displacement of the continuity of the rock occurrence. The variability of the elements of seam occurrence and the strong disturbance create considerable difficulties in developing the deposit.

Methods of Preparing Levels and Driving Workings

In all mines of the district, opening is carried out by vertical shafts and level crosscuts. Preparation of the levels is carried out by group drifts and intermediate crosscuts. In this arrangement, the suite of seams is divided into two groups. For the upper group of seams, Desyatyi and Andreevskii, the group drift is driven along the Andreevskii seam; for the lower group—Dvoinoi, Petrovskii, Tonkii, Sluchainyi, Koksovyi—it is driven along the Petrovskii seam. Intermediate crosscuts in each group of seams are driven every 300–350 m. In view of the great difficulty of maintaining seam workings, the group drifts are driven as single-track workings with sidings.

Single-track group drifts often do not ensure the normal operation of underground transport or the passage of a sufficient quantity of air for ventilating the wing of the mine field, especially when several levels are being worked simultaneously. Therefore, in three mines of the district, except—

Table 1

Characteristics of the seams of the Central Adit

…in addition to group seam drifts, field drifts are driven; these are located in the rocks of the floor of the Coking seam.

In seams developed through a group drift (Tenth, Coking, and others), single-track haulage drifts with passing sidings are driven. As the extraction panels are worked out, these drifts are usually abandoned. Only in the northern wing of the mine field of Mine No. 5—7 is the main drift of the Coking seam maintained along the entire length of the wing. In addition to the workings indicated, when preparing closely spaced seams and disturbed sections, rises are driven.

The specific extent of maintained workings per 100 m of longwall face and per 1000 t of output is presented in Table 2.

Table 2

Specific extent of maintained workings per 100 m of longwall face and per 1000 t of output

All seam haulage drifts are driven with a narrow face. The rock from blasting is usually brought to the surface. Coal and rock are broken by blasting, with the advance per cycle not exceeding 1.2–1.5 m.

The support of group drifts and main crosscuts is made of metal. Most often metal arched support made of special sections is used; less often, trapezoidal support made of I-beams and rails. The remaining horizontal workings are timber-supported. Metal support is used most extensively at Mine No. 5—7. Here 43.2% of all maintained workings are supported with metal and concrete (including mine shafts and workings of the shaft-bottom yard); the remaining 56.8% of workings are supported with timber. At Mine No. 9—15 only about 30.0% of workings are supported with metal and concrete, and at the other mines even less. Precast reinforced-concrete support is not used at all in the mines of the district.

For the maintenance of group seam drifts, coal pillars 15–20 m in size along the rise are left. Operating experience has shown that, when the levels are worked in direct order, pillars of such dimensions are not sufficiently stable. Under the influence of the caved rocks of the longwall workings, they shift down the dip of the seam toward the haulage drift and cause deformation of the support.

Methodology for Determining the Cost of Maintaining Haulage Workings

To determine the cost of maintaining 1 linear m of haulage workings per unit time, extended workings were selected (more than 500 m long), with a long service life and with different maintenance conditions. For each of them, on the basis of mine-work plans, surveyors’ measurement books, shift reports of mining foremen, and payroll statements, data for 2.0–2.5 years were identified according to the following indicators:

1) the volume of work performed in repairing the support;
2) the number of man-shifts spent on repair;
3) the direct wages of workers engaged in repair;
4) the length of the working at the beginning and end of maintenance;
5) maintenance conditions.

On the basis of these data the following were calculated:

1) the number of sets installed per 1 linear m of the maintained working per year;
2) the number of man-shifts spent per 1 linear m of working per year;
3) the direct wages of workers per 1 linear m of working per year;
4) the full cost of maintaining 1 linear m of working per year.

In determining the cost of maintaining a working on the basis of practical data, repeated use of metal support was taken at 20.0% of the installed sets. Transport of rock and materials and repair of rail tracks were not taken into account.

Form No. 1

Name of working ______

Mine ____ Horizon ____

Seam __________

For uniformity in the method of obtaining initial data and determining the cost of maintaining 1 linear m of working per year, all data were entered in a special form (Form No. 1). The determination of the cost of maint—

of roadway maintenance on the basis of primary documentation was adopted at DonUGI and at present is the basic method.

In all, 22 haulage workings were examined; of these: 17 in-seam haulage drifts, 2 crosscuts, and 3 field drifts.

Cost of Maintaining In-Seam Haulage Drifts

The in-seam haulage drifts examined can be divided, according to maintenance conditions, into 3 groups: 1) drifts maintained in an undisturbed coal massif; 2) drifts maintained in the zone of the worked-out space during the period of extraction operations; 3) drifts maintained in the zone of the worked-out space after the completion of extraction operations in the panel and after complete replacement of the support in them.

The most characteristic workings of the first group are: 1) the Third Western haulage drift of the Petrovsky seam, 2) the Third Northern haulage drift of the Andreevsky seam of horizon 336 m at mine No. 9—15, 3) the Central haulage drift of the Petrovsky seam of the “Andreevskaya II” mine.

The Third Western haulage drift of the Petrovsky seam and the Third Northern haulage drift of the Andreevsky seam are driven as single-track workings with sidings, with a cross section of 8.25 m². Support is provided by metal arch supports. Where metal supports are lacking, timber is used. The sidings are supported with timber. The frames of the metal support are set at intervals of 0.7—1.75 m, while timber frames are set continuously. The Central drift of the Petrovsky seam at the “Andreevskaya II” mine is driven as a double-track working and is timber-supported.

Fig. 1. Cost of maintaining 1 linear m per year of the Third Western haulage drift of the Petrovsky seam, horizon 336 m, mine No. 9—15

Materials on the maintenance of these drifts were collected for the period from January 1954 to June 1956. The summarized results of the analysis of drift maintenance in an undisturbed coal massif, presented in the graphs (Figs. 1, 2), show the following:

1) the cost of maintaining 1 linear m of drift per year is 115—155 rubles;

2) an increase in the length of workings from 550 m to 850 m and even to 1500 m had no effect on the cost of their maintenance;

Fig. 2. Cost of maintaining 1 linear m per year of the Third Northern haulage drift of the Andreevsky seam, horizon 336 m, mine No. 9—15

3) stoping operations in the Andreevskii and Petrovskii seams, begun in 1955, did not affect the cost of maintaining the drifts.

The workings of the second group include the following: 1) the haulage drift “Third Western” of the Andreevskii seam, horizon 336 m; 2) the haulage drift “Third Western” of the Tenth seam, horizon 336 m; 3) the southern haulage drift of the Koksovyi seam, horizon 226 m, of mine No. 9—15; and 4) the first haulage drift of the Andreevskii seam of the “Andreevskaya II” mine.

The haulage drift “Third Western” of the Andreevskii seam, horizon 336 m, of mine No. 9—15, is driven as a single-track working with cut-throughs, with a cross section of 7.8—8.25 m². The drift is supported by metal arch supports and timber. The greater part of the working is supported with metal. The cut-throughs are supported with timber. The drift is maintained mainly in the goaf area, while stoping operations are carried out in the Bremberg and inclined panels.

The results of the analysis of materials on the maintenance of this drift, shown in the graph (Fig. 3), indicate that the cost of maintaining

Fig. 3. Cost of maintaining 1 linear meter per year of the haulage drift, Third Western of the Andreevskii seam, horizon 336 m, mine No. 9—15

1 linear meter of drift per year is 218.0 rubles; the number of sets per 1 linear meter per year is 2.0.

The first haulage drift of the Andreevskii seam of the “Andreevskaya II” mine, with a cross section of 8.25 m², is supported by continuous timbering and has an average maintained length of 450 m. The average cost of maintaining 1 linear meter of drift per year in the second year of its service was 215.0 rubles; the number of sets per 1 linear meter per year was 1.7. The nature of the change in maintenance costs over time is approximately the same as in the preceding drift.

The single-track haulage drift “Third Western” of the Tenth seam, horizon 336 m, of mine No. 9—15, with a cross section of 8.25 m², is usually driven without cutting the side rocks. The drift is supported with timber. The support sets are installed continuously. Usually the drift is maintained over a short length (300—500 m), since as the extraction panels are worked out it is abandoned. The average cost of maintaining 1 linear meter of drift per year is 253.0 rubles; the number of installed sets per 1 linear meter per year is 3.0.

Observations have established that deformation of the support in the drifts of this group occurs from the side of the protective pillar.

Of the workings of the third group, 8 haulage drifts were examined, which, in terms of service life and level of maintenance costs, conditionally are divided into ...

divided into two subgroups. The first subgroup, with a service life of 7 years, includes the following haulage drifts: the 5th south and 6th north of the Petrovsky seam, the Fifth south and Sixth north of the Koksovy seam, and the Sixth north of the Dvoynoy seam, horizon 300 m, mine No. 5–7. All the listed drifts were driven as single-track workings with passing sidings, with a cross section of 7.0 m². At present they are supported mainly by metal arch supports. Timber supports have survived only in some sections (junctions, passing sidings). The frames of the metal supports are installed at intervals of 0.7 m, while timber supports are continuous. To support the drifts, coal pillars measuring 15–20 m have been left on all seams. Below the drifts there is a solid coal mass. Most often the support of the workings is deformed from the side of the protective pillars. The annual cost of maintaining 1 linear meter of these drifts

Fig. 4. Cost of maintaining 1 linear meter per year of the haulage drift of the 6th north of the Dvoynoy seam, horizon 300 m, mine No. 5–7

per year varies from 70.0 to 100.0 rubles. The number of installed support frames ranges from 0.58 to 0.65. The change over time in the amount of expenditures for maintenance, shown in the graphs (Figs. 4, 5), is characteristic

Fig. 5. Cost of maintaining 1 linear meter per year of the haulage drift of the 6th north of the Koksovy seam, horizon 300 m, mine No. 5–7

of workings maintained in the zone of established rock pressure in collapsed rocks.

The second subgroup is represented by the Eighth north and Sixth south-

...by the main haulage drifts of the Andreevsky seam, horizon 300 m, of mine No. 5–7, which have an even longer service life—12 years. Both drifts were driven as single-track workings with sidings, with a cross section of 7.0 m². At first the drifts were supported with timber supports, which were gradually replaced by metal supports. At present they are supported with metal along their entire length. To maintain the drifts, coal pillars measuring 15–20 m along the rise were left. Below the drifts there is a solid mass of coal. As established by observations, deformation of the support always occurs on the side of the protective pillar. A study of the materials on the maintenance of these drifts established that the average cost of maintaining 1 running m per year is 55.0 rubles; the number of installed metal frames per 1 running m per year is 0.4. The characteristic change in maintenance costs over time is shown in the graph (Fig. 6).

Fig. 6. Cost of maintaining 1 running m per year of a haulage drift of the southern Andreevsky seam, horizon 300 m, mine No. 5–7

An analysis of the materials on the maintenance of 17 seam haulage drifts and the observations carried out make it possible to draw the following conclusions.

1. The cost of maintaining 1 running m of seam haulage drifts per unit of time depends to a significant degree on the conditions of their maintenance. The highest cost is found in workings maintained in the zone of the goaf during stoping operations (215–253 rubles per running m per year). Workings maintained in the zone of the goaf after completion of stoping operations have minimal maintenance expenditures (50.0–100.0 rubles per year); moreover, as the service life of the working increases, they decrease. This confirms the data of DonUGI that the cost of maintaining ventilation drifts is lower than that of haulage drifts. Considerable maintenance costs are incurred by workings maintained in an undisturbed solid coal mass. The cost of maintaining 1 running m of a working of this group per year is 100.0–150.0 rubles. This circumstance may be explained by the insufficient yielding capacity of the primary support.

2. The greater part of the expenditures on maintaining a working consists of expenditures on materials. In the workings examined, they amount to 65–70% of all expenditures.

3. Protective pillars measuring 15–20 m on seams more than 1.5 m thick, under the influence of the collapsed rock of stoping workings, are displaced down the dip of the seam toward the haulage drift. As a result, deformation of the support of seam haulage drifts always occurs on the side of the protective pillar.

4. In seam haulage drifts, metal haulage support made of special profile, as compared with trapezoidal support made of I-beams and rails, is more stable and requires lower repair expenditures.

5. The cost of maintaining 1 running m of a working per unit of time in

under the conditions considered in the Anzhero-Sudzhensk district, it practically does not depend on the length of the working for lengths of a mine field customary for Kuzbass.

Cost of Maintaining Workings Driven in Rock

As was indicated above, a total of 5 workings driven in rock were examined; of these, 2 were crosscuts and 3 were district haulage drifts.

The central crosscut at horizon 226 m of Mine No. 9–15 was driven as a single-track working with passing bays, with a cross section of 8.25 m². The crosscut was supported mainly with timber. The length of the working at the beginning and at the end of the collection of maintenance data was 1200 m. As a result of the investigation it was established that the cost of maintaining 1 running m of the crosscut per year is 47.8 rubles; the number of sets per running m per year is 0.61.

The central crosscut at horizon 336 m of Mine No. 9–15 was driven as a double-track working with a cross section of 11.3 m² and supported with steel support. The length of the crosscut at the beginning and at the end of the collection of data on its maintenance was 1495 m. Deformation of the support most often occurs from the roof side of the working. The results of the analysis of the data on maintenance of the crosscut are presented in the graph (Fig. 7), from which it is seen that the cost of maintaining 1 running m per year is 22.0 rubles, i.e., twice less than the cost of maintaining the central crosscut at horizon 226 m. The number of installed sets per 1 running m per year is 0.1.

Fig. 7. Cost of maintaining 1 running m per year of the main crosscut at horizon 336 m of Mine No. 9–15

The comparatively high cost of maintaining the main crosscut at horizon 226 m is explained not only by the use of timber support, but also by the unfavorable influence of physical and biological factors, which intensify as a result of the long service life of the crosscut.

The district haulage drifts, the First Southern and the First Northern at horizon 300 m of Mine No. 5–7, were driven in strong sandstones as single-track workings and with a cross section of 8.25 m². Their support was made of timber, which at present is being replaced by steel support (during repairs). The average length of the drifts is: the First Southern—1600 m, the First Northern—1160 m. The average cost of maintaining 1 running m of these drifts per year is 30.0 rubles; the number of installed support sets is 0.16. The change in expenditures for maintaining the drifts over time is shown in the graph of Fig. 8.

The single-track northern district haulage drift at horizon 200 m of Mine No. 5–7 is supported throughout its entire length with steel support, with trapezoidal support being the most widespread. The length of the drift is 2837 m. On the basis of the analysis of the data on maintenance of the drift it was established that the average cost of maintaining 1 running m per year is 13.5 rubles; the number of installed support sets per 1 running m per year is 0.04.

A comparison of the unit costs for maintaining workings driven in rock, and the observations made of the condition of the supports and their repair, make it possible to draw the following conclusions:

1) the annual cost of maintaining 1 linear m of a working with metal support is 2–3 times less than that of workings with timber support;

2) the unit costs of maintaining two-track workings are approximately 1.5 times higher than for single-track workings;

Fig. 8. Cost of maintaining 1 linear m per year of the field haulage drift 1 south horizon 300 m of mine No. 5–7

3) the length of workings of the same type has no effect on the cost of their maintenance.

The absolute direct costs of maintaining workings under the conditions of the Anzhero-Sudzhensk district may be taken according to the average values of the graphs presented (Figs. 1–8).

REFERENCES

1. Lebedev A. N. Maintenance of mine workings in the mines of the Karaganda basin. Ugletekhizdat, 1954.

2. Rozenberg S. E. The cost of maintaining mine workings supported with timber. Ugletekhizdat, 1952.

3. Davidyants V. T., Kogan A. B. The cost of maintaining development workings supported with new types of supports. Ugletekhizdat, 1956.

NOTED MISPRINTS

Publ. TPI, vol. 103.