Kon lahimlarini barрo

Excavation of mines basics of doing
Plan:
and main properties of mining rocks
2. Reinforcement materials
3. Mine solder reinforcement


and main properties of mining rocks

An untouched (intact) mine array is always in a state of equal stress . Therefore, each ore particle located at a certain (N) depth is affected by the following stresses: along the vertical axis - dz=CH ; along the horizontal axis - dx=du=lCH. Here, H is the depth from the surface of the earth to the particle, m; C - volumetric weight (density) of mining rock, kN/m3 l - coefficient of lateral tension.l= µ( 1-µ)

Here, µ is the Roisson coefficient (0.1–0.4 for mining rocks, on average 0.2–0.25). Under the influence of these stresses, each mining rock particle
of equal intensity. It can be seen that
intact (untouched) earth's crust do not move almasand change their shape until they are affected by something from the outside (Fig. 2.1). undergoes deformation. Because as a result of welding, stresses are redistributed in the massif surrounding it, as a result, the weld gap of the mine rocks
moves towards This movement of the rocks is called deformation.
Necessary measures are taken against the development of deformation of mining rocks.
removed , then the rocks of the mine will be damaged and fill the pit
can _ The main measure used against this is mining. Fig. 2.1. State diagram of solid rock.
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artificially strengthen the joints. It is installed in this
the reinforcement absorbs the pressure of the mine rocks and prevents the rocks from falling into the weld cavity. According to Professor MM Rrotodyakonov's gyrothesis , a pressure dome is formed on the terrace of the mine, and this dome absorbs the pressure of the rock layers above. As a result, the load on the reinforcement is equal to the weight of the mine rock between the solder ceiling and the upper border of the dome (Fig. 2.2). Therefore , the amount of mine pressure does not depend on the depth of the mine
be concluded . In horizontal welds, if their side walls
lar is not strong (stable), the vertical load on the reinforcement is determined by the following expression :
qv= gh1 Where qv is the vertical load on the reinforcement, kN/m
g - specific weight of the rock , kN/mh
1 - the height of the failure dome, m.
h=L :2f where L is the maximum width of the failure dome, m;
– rock hardness according to the MM Rrotodyakovon scale
coefficient .
245 (2r
− − = htg BL
Here, B is the width of the seam, m.
H is the height of the weld, m.
seen from the above expressions , the method, mechanisms, welding process used in mining
Figure 2.2. The scheme for determining the dimensions of the collapse dome.
It is important to choose the order of organizing your work
massif to be moved and the rocks contained in it. The main properties of mining rocks that affect the formation of mine deposits and their preservation over a certain period of time: stability (solidity) of the mine massif, abrasiveness (abrasiveness), hardness, elasticity, porosity, fissures, ductility, fluidity and others. The properties of coal and ores when separated from the massif include fragmentation, crushing, burning and rusting.
like . Mining massif and mining rocks are listed above
properties are , first of all, the main factor in choosing mining technology options. The hardness of rocks is their relative resistance to damage (crushing) under the influence of external forces during mining . For example, resistance to damage caused by drilling, drilling and mine pressure. The degree of hardness of mining rocks is determined by the dimensionless coefficient recommended by professor MM Rrotodyakonov, and this coefficient varies from 1 to 20. Abrasion is a feature of impact on the erosion of mining machine parts as a result of rubbing against the rocks during the processes of mining and loading them.
Mining rocks and minerals are divided into 5 categories according to abrasive properties: a) rocks without abrasive properties (salt , manganese ores, coal); b) less abrasive rocks (sulphide ores, brown ironstones); d) moderately abrasive rocks (quartz-sulphide ores and earthen ores); e) abrasive rocks (quartzized ores and slanes); f) highly abrasive rocks (rorphyrites, diorites, granites).
Usually, the high level of abrasiveness of rocks with a high hardness coefficient has been confirmed in mining practice .
is the property of maintaining the balance of the mining massif in the spaces created as a result of mining operations . The stability of ore and coal is important in the technology of mining operations and maintaining the excavation space.
is important . ! In the underground mining of mineral deposits (ore deposits), the massif of mining rocks is classified according to stability as follows:
length , V is the width of the piece and C is the height of the piece. In practice , fragmentation is characterized by the presence of large fragments in crushed ore , which is measured in percentages. ( The large pieces are called " oversize " and such pieces are larger than the dimensions of the working bodies of the loading machines and the ore unloading ladles).
Grinding is the property of the crushed ore or pieces of mine rock becoming monolithic over time.
rocks extracted from the massif is greater than their volume in the massif and is determined by the ratio of the volume of crushed ore rocks to the volume in the massif .