Institute of Mining and Geology
Speciality: Safety of labour activity
Experience the mines of the Central District of Donbass shows that with increasing depth of working out the development of coal bed is complicated by the relevant mining-geological conditions: the presence of unstable country rocks, changing the intensity of shifts and the shape of their manifestations, cave roof and sliding rocks of soil. This situation poses a serious danger and leads not only to the destruction of mines, but also to the injury of workers.
Analysis of industrial injuries of rockslide on the 1998 - 2008 he pointed out that about 65% of the injuries accounted for stope, 22% in the face of development workings and about 12% to perekreplenie workings. To reduce injury to these factors is necessary to develop modern science-based measures aimed primarily at improving the stability of the wall rocks.
Under the theme of the Ministry of Coal Industry of Ukraine — "The program works to improve the safety of coal mines"
Reducing injury in the development of steep seams outburst on modern depths
1. Analytical study stability of the wall rocks
2. Laboratory study the stability of wall rocks
3. Mines experiment.
Patterns of discharge of the wall rocks to ensure the stability of mine workings, without which the decline in injuries can not
At present, Ukraine's mines have very low technical and economic performance primarily because of the complexity of mining, especially the Central Donbass region with a steep bedding layers and the consequent effect on their behavior, exacerbated by the large number of layers, which are prone to sudden outbursts of coal and gas, and layers with self — igniting coals, as well as high temperatures surrounding rocks, increasing with increasing depth [1].
At mines with steep strata apply solid, pillar, and the combined system development [5]. Despite the shortcomings of the continuous system and the benefits of pole, the volume of the latter does not exceed 4%. Comparison of technical and economic indicators for the comprehensive mechanization of stope shows that when a continuous system load on the lava more than columnar and combined. One reason for this is that the comprehensive mechanization is applied, usually in a favorable geological conditions. Coal extraction by means of complex mechanization in columnar and mixed systems is only seams in the complex environment of occurrence, as well as the seams are prone to sudden outbursts of coal and gas.
Most common in the central region of Donbass had such control methods of rock pressure in the stope, as the retention of the roof at the stake, its complete collapse and gradual subsidence [7]. Distribution,%, faces on how to roof control on steep seams is given in the table.
In comparison with 1970 number of production faces with the management of the roof retaining the stake has increased by 19,7%. This was mainly due to the deteriorating geological conditions, but the method itself has changed significantly. It is known that the steep seams collapse of the roof, usually starts at the top of the lava, and then distributed irregularly, with separate sections along its entire length.To achieve uniform rockslide began to apply a special support with high load capacity that is installed on the strike, but the probability of precipitation of the main roof has not diminished.Obviously, this is because there are uncontrolled subsidence of the wall rocks along the normal and the plane layer, which is applied lining can not resist.
It is believed that the most promising method of control should be included under the roof of a complete collapse. However, the existing technology of its execution is no different from the control roof retention at the stake.
Methods of development workings entirely coal, rubble strips, various designs izdereva often do not provide reliable protection from rock pressure or complicate the technology of preparation and clean-up operations. More efficient use of complex equipment with mechanized supports and panel units is constrained by the unsatisfactory state of reservoir openings and need a way to keep them satisfying the requirements of productive work safely clean faces [2].
Of particular importance is finding a universal method of workings. In this way, as shown by preliminary studies, is a bookmark developed space Crushed rock backfill to shrink the array by 30%.Indeed, when lag backfill array from the face at 3 - 3,5 m and its shrinkage to 30% continuity of settling rock is not disturbed. This is characteristic of developed space.
The main means of mechanization of coal extraction in the stop on the steep seams are hammers. In 1996, with their help, produced 70% of all coal. The reasons for holding back the pace of work on the mechanization of fixing and control of rock pressure — in the specific characteristics of the dip, causing the need for additional special requirements for the means of extraction, as well as insufficient knowledge of the regularities of pressure and the interaction supports with lateral and rock slide to select promising schemes.
Analysis of results of complex equipment with mechanized propping destined for slaughter with a complete collapse of the roof, shows that the specific conditions under consideration does not allow to count on continued reliable operation of production faces the variety of geological conditions of occurrence of steep seams and experience in the mines, should focus primarily on the full tab of the area mined [6]. And the technology must take into account the diagonal groove arrangement with the slope hanging over him stowing the array that best fits the conditions of work and testing of powered supports layers, which are prone to rashes and dangerous to sudden outbursts of coal and gas.
Static load acting on the fence lining, increasing with the departure of the complex from the furnace and sectioned, reaching the maximum, leading to the formation of the tied efforts reversal sections support at their unloading and shifting. This question is not simplified, and becomes more complex with full collapse, especially in the upper part of the stop, where the rocks are periodically attacked, will create alternating static and dynamic impact on the fence lining [4].
Go to the comprehensive mechanization of the steep seams requires a filler powered supports lightweight construction, which could support the wall rocks at the two poles, save road head for posting it excavation machinery, airing breakage face, hold road head penetration rock slide [3].
The development of steep seams complicated deteriorating geological conditions and the increasing number shahtoplastov prone sudden outbursts of coal and gas. Under the current scheme of preparation and order mining floors at the same time work can find two or more layers. This order is characterized by deconcentration of work. The most rational for the conditions considered to be block training excavation sites and the separation of floors at substances.
Given the variety of geological conditions of occurrence of steep seams and experience in the mines, must focus on the application of a universal way of controlling the roof — a full tab of the area minedysis of production costs for coal mining, with the full tab of developed space shows that an increase in their numbers greatly reduced costs for training backfill materials and the specific depreciation. This reduces the cost of coal and improve backfill work.
Technology and equipment for the extraction of steep seams must be determined by such requirements: the slope face at an angle, eliminating the influence of gravitational forces on the eruption of coal; shifting sections upwards, overhanging the stop backfill array and the distance between them within 3 - 3,5 m . Application backfir improves the wall rocks and increases the stability of reservoir development workings. Backfill array having suppleness, prevents the development of intensive fracturing.
© DonNTU, Khudoliei T.O.