RECONSTRUCTION OF THE CRUSHING PLANT AT THE STALIN MINE IN PROKOPYEVSK

M. M. Savkin

The Stalin Mine (“Koksovaya”) is one of the largest mines in Europe. Its design output is 2.5 million tons of coal per year. The mine works the thick coal seams of the Prokopyevsk mine field—this pearl of Kuzbass. The coal in some of these seams is prone to spontaneous combustion, and therefore the mining systems must be such as to preclude the possibility of the coal’s self-ignition. A particular evil, inevitably and unavoidably entailing spontaneous combustion of coal and the development of underground fires, was the system of working by chambers with caving, persistently practiced by the wreckers in Kuzbass, who built for the Koksovaya mine a crushing plant for obtaining stowing material to fill the space worked out underground. With enormous delays, this plant was completed by installation at the beginning of 1935, but when its equipment was put into operation, some of those present literally ran out into the street, fearing that in the terrible roar a breakdown would occur immediately and pieces of parts would fly in all directions.

The equipment of the plant consisted of the following units, in the order of their arrangement from the rock bunker to the mine (see the diagram in Fig. 1): chain feeders with chains of round iron 50 mm in diameter; eccentric screens with maximum openings of 80 × 80 mm; Blake crushers; and again eccentric screens for the final separation of large pieces after the crushers.

When the units of the crushing plant were started, the chain feeders began to operate with such a large number of revolutions that they not only failed to hold back the rock but, winding themselves onto the drive sprockets, struck the wall, became tangled, and threatened to break the drive gears and shaft. The screens became buried in rock and, after several minutes of operation, jammed from pieces of rock stuck between the eccentrics and broke the drive gears.

After the first testing of the units, which showed the impossibility of operating the equipment assembled in this way, ...

Fig. 1.

Labels in the figure:

• chain feeder
• Blake crusher
• screen 1
• screen 2
• to the reversible conveyor

Fig. 2.

Label in the figure:

• diagram 2

Fig. 4.

Labels in the figure:

• diagram 4
• top sprockets
• chain of flights
• flywheel

Fig. 3.

…tion, the plant was stopped. A special man, an engineer, was summoned from Kuzbassshakhtostroi and assigned to eliminate the malfunctions in the plant’s operation.

A year passed in “adjusting” the plant’s units. Some of the gear transmissions were replaced by belt drives, which eliminated the breakage of gears, but did not eliminate the jamming of the screens. The chain feeders continued to operate unsatisfactorily. The chains wound themselves onto the driving sprockets. In order to be able to run the screens for several minutes, workers with heavy hammers were stationed on both sides of them and were given the task of breaking up the pieces of rock that jammed the screens. Naturally, it was impossible to operate the plant under such conditions. Since this could not continue for long—the rock was needed for stowing—the chief mechanic of the mine, an enemy of the people, issued an order to throw out the almost new screens and to place simple rails instead of them before the crusher, and to remove the screens after the crusher altogether. The feeders were stopped, the chains removed, and the rock was fed into the crusher by hand. At the same time, having finally rejected the screens, the mine administration ordered new disk screens from the Kemerovo Mechanical Plant.

Contrary to the decision of the mine administration, we raised the question of the possibility of using the existing equipment. At our energetic insistence, the mine administration decided to inquire of specialists about the possibility of using eccentric screens for work on rock. In June 1936, inquiries were sent to TsITÉIN, to the Moscow Mining Institute, to the Irkutsk Mining Institute, and to the Sverdlovsk Mining Institute, to the appropriate departments. In July two replies were received: one from TsITÉIN, stating that in this particular case no assistance could be given, and one from Prof. Levenson, who gave a description and the conditions of normal operation for Distl–Zucke screens having triangular cams, which did not correspond to the conditions of the inquiry. Despite the fact that unsatisfactory answers had been received, we obtained permission for a one-month experiment in starting up the existing equipment.

A careful study of the operation and malfunctions of the equipment showed that the chain feeders were making approximately six times more revolutions than they should have. In addition, it turned out that the reason the chains wound themselves onto the driving sprockets was that each feeder chain had an odd number of links, which determined an incorrect mutual alternation of the links at a given position of the chain. Observing the chains during operation (after reducing the number of revolutions), one could notice that the chain, as it were, was constantly turning about its longitudinal axis, and as soon as this turning did not occur, the chain began to wind itself onto the sprocket. After the “extra” link had been cut out and an even number of them left, the chains stopped winding themselves onto the driving sprockets. Incidentally, in order to reduce…

To reduce the number of revolutions of the chain feeders, the old drives of the DK-5 swinging conveyors were used; in these the crankshaft was replaced by a straight one, lengthened so that a driving pulley could be mounted on its end. The result was a very cheap reduction gear, which made it possible to reduce the number of revolutions of the chain feeders to a normal value (3.5 rpm).

Studying, with the help of the workers who had had to work during the plant’s start-up period, the malfunctions that had occurred in the operation of the screens, we came to the following conclusions:

First, the angle of inclination of the screens was small; and second, if the screen rollers were left in their former relative arrangement, it would not be possible to eliminate jamming (see the diagram in Fig. 2). Therefore we attempted to change the arrangement of the rollers on the frame and placed them so that the eccentrics were arranged in a staggered pattern (see the diagram in Fig. 3). It was assumed that a piece of rock that got between the eccentrics of one roller would be knocked out by the eccentric of the neighboring roller. After a trial run of the newly mounted screens, our assumptions were confirmed. However, in some cases jamming still occurred, since the neighboring eccentric developed insufficient force on the “wedge” and could not squeeze it out.

In order to intensify the wedging-out action of the neighboring eccentrics, we mounted flyweights on the drive shaft (see the diagram in Fig. 4). Now, in the event of jamming, the eccentrics acted on the piece of rock stuck in the rollers like a hammer and either pushed it downward or crushed it. Naturally, this increased the wear of the eccentrics themselves, but it solved the problem of eliminating the “wedges,” which were the main obstacle in the operation of the screens. Having resolved the question of the possibility of using the discarded equipment, which had cost about 40 thousand rubles, and with the support and participation of the crushing-plant workers’ collective, we succeeded in putting it into operation and canceling the order for new screens for this plant.

After a little more than two years, i.e., in November 1938, we inspected the crushing plant, which to this day continues to operate satisfactorily with the equipment that had once been finally rejected and discarded. Some of the eccentrics have worn appreciably, but the cost of repairing them, or even replacing them, is negligible compared with the cost of the screen. Incidentally, when reviewing the design of this crushing plant after all questions of putting it into operation had already been resolved, we found that the design, with respect to the selected screens, stated: “the screens are intended for operation on coal.” And nevertheless they had been installed for rock, with the obvious purpose of causing permanent breakdowns and thereby disrupting the stowing work at the largest mine in the Union. This calculation, however, failed. Today the authors of these acts have suffered severe punishment.

We, young specialists, must draw from this example a profound lesson in how sometimes seemingly innocent, at first glance, produс—

Operational malfunctions and “technical” breakdowns in fact have as their cause the hostile activity of certain enemy elements. At the same time, while exposing and rooting out hostile elements from our midst, we must dare to experiment, overturning established, obsolete norms and traditions. And from revolutionary daring will be born new indicators, new norms, new machines, new people bearing communism with them.