RU2282720C1 - Underground mining method in areas having limited dimensions - Google Patents

Abstract

FIELD: mining, particularly underground mining of flat-lying mineral seams, preferably salt and coal seams.

SUBSTANCE: method involves serially developing two mineral columns with single long face; cutting the first columns with face moving towards working area border; forming bypass excavation along outer border of working area; driving local and panel preparation excavations; forming stoves between panel and local preparation excavations; turning long face at working area border along with following cutting the second column with long face in direction opposite to the first column cutting direction. The first local preparation excavation is driven along inner border of the first column. The second reusable local preparation excavation and panel preparation excavations are driven within area occupied by the second column. Panel preparation excavations are spaced a distance from inner border of the first column. The distance exceeds width of critical stress area generated over mineral seam edge. Distance between local preparation excavations is equal to extreme width of pillar located in excavated space. If pillar width is less than above extreme width the pillar is broken by rock pressure. The stoves are formed in front of long face between panel and local preparation excavations during the first column cutting and between panel preparation excavations and bypass excavation during the second column cutting. If stable hard rock is positioned directly in mineral seam roof long face length is equal to distance between bypass excavation and inner border of the first column. If unstable fractured rock is positioned directly in mineral seam roof long face length is equal to distance between reusable preparation excavation and bypass excavation part located from virgin massif side.

EFFECT: reduced mineral losses.

3 cl, 4 dwg, 1 ex

Description

The invention relates to the field of mining and can be used in underground mining of shallow layers of minerals, mainly salt and coal, in areas of limited size.

A known method of underground mining of mineral deposits in areas of limited size, including the conduct of local preparatory workings and sequential mining of two adjacent mineral pillars by lavas (RF Patent No. 2101497, Bulletin No. 1, 1998). Sites with limited dimensions are understood as excavation sites whose large sizes are less than the optimal length of the column.

The first pillar is refined with lava moving from the main preparatory workings towards the boundary of the excavation site. At the boundary of the excavation site, the equipment in the first lava is dismantled. The split lava furnace working off the second pillar is held in line with the dismantling chamber of the first lava before the dismantling of equipment in the first lava. The second pillar is worked out in reverse from the boundaries of the excavation site to the main preparatory workings. The disadvantages of this method are: significant costs for the installation and dismantling; economic damage associated with the downtime of treatment equipment; high costs of maintaining local preparatory workings.

There is also known a method of underground mining of mineral strata in areas of limited size, including the sequential mining of two adjacent mineral columns of one lava. Pillars are tested in mutually opposite directions. On the border of the excavation site, a lava is turned. At the same time, at the pivot center, a group of sections of the lava mechanized roof support is dismantled for the duration of the pivot, and the roof in this section of the lava is supported by individual support (Auth. St. USSR No. 578457, Cl. E 21 C 41/04, BI No. 40, 1977) . The disadvantages of this method are the significant costs of maintaining the preparatory workings, the high complexity of installation and dismantling works and the increased intensity of the collapse of the roof rocks in the lava area adjacent to the center of the reversal.

A known method (adopted as a prototype) of underground mining of mineral strata in areas of limited size, comprising sequential mining of two columns of minerals with one lava, mining the first column of lava moving towards the boundary of the excavation section, conducting an outer circumference of the mining excavation section development, conducting precinct and panel preparatory workings, conducting furnaces between panel and precast preparatory work with lakes, turning the lava at the boundary of the excavation site, followed by mining the second pillar of lava in the direction opposite to the direction of mining the first column, bypassing and turning the lavas at the boundaries of the excavation field from the spent mining columns to the pillars to be mined (Auth. USSR USSR No. 863860, Cl. E 21 C 41/04, Bulletin No. 34, 1981). The disadvantages of this method are the significant costs of maintaining the preparatory workings and significant losses of minerals in the pillars left between the extraction columns.

These disadvantages are due to the fact that when using the known method (prototype) between pillars leave pillars of a mineral of considerable width. Losses in these pillars reach 20-30% of the balance reserves of the excavation site. Preparatory workings located between the working columns are negatively affected by the reference pressure, which is formed both in front of the lava and at the edge parts of the mineral massif, which results in significant costs for maintaining the preparatory workings.

The technical result is the elimination of these disadvantages of the known prototype method, namely the reduction of mineral losses and the cost of maintaining preparatory workings.

The technical result is achieved by the fact that the claimed method of developing mineral deposits in areas of limited size includes the sequential mining of two columns of minerals with one lava, mining the first column of lava moving towards the boundary of the excavation section, drawing along the outer boundary of the excavation section of the bypass excavation, local and panel preparatory workings, conducting furnaces between panel and local preparatory workings, a U-turn lava at the boundary of the excavation site with subsequent mining of the second column of lava in the opposite direction to the mining of the first column.

According to the invention, one local preparatory development runs along the inner border of the first pillar, a second reusable local preparatory development, as well as panel preparatory workings pass within the area occupied by the second column. When mining the first pillar of the furnace pass in front of the lava between the panel and local preparatory workings, while mining the second pillar of the furnace pass between the panel preparatory workings and bypass workings. In this case, the panel preparatory workings pass at a distance from the inner boundary of the first column, greater than the width of the zone of increased stresses arising above the edge of the mineral layer, and the distance between the local preparatory workings is taken equal to the limiting width of the pillar located in the worked out space, which decreases pillar with mountain pressure.

When the solid stable rocks are located in the immediate roof of the mineral layer, the length of the lava is taken equal to the distance between the bypass working and the inner border of the first column.

When a fracture of unstable rocks is located in the immediate roof of a mineral layer, the length of the lava is taken to be equal to the distance between the reused local preparatory mine and the bypass mine located on the side of the untouched massif.

The essence of the proposed method is illustrated by the diagrams presented in figure 1 - 4.

Figure 1 shows a schematic diagram of a mining site with limited dimensions (plan view) during the development of the first column.

Figure 2 shows a schematic diagram of a mining site with limited dimensions during the development of the second column when bedding in the immediate roof of the mineral layer of fractured unstable rocks.

Figure 3 shows a schematic diagram of a mining site with limited dimensions during the development of the second column when bedding in the immediate roof of the mineral layer of strong stable rocks.

Figure 4 shows a schematic diagram illustrating the nature of the distribution of stresses in the zone of reference pressure that occurs above the edge of the array, and the location of the precinct and panel preparatory workings relative to the worked out space.

Figure 1 - figure 4: NBCLM - excavation section; CLM - the boundary of the excavation site, on which the turn of the lava; ABCLO - the first pillar of minerals; ALMN is the second pillar of mineral; AO - the internal border of the first pillar of minerals; 1 - bypass output;

2, 3, 4 - panel preparatory workings; 5 - furnaces; 6 - reused precautionary development; 7 - local preparatory development, passed along the inner border of the first pillar; 8 is a diagram of the stress distribution (σ _z ) in the zone of reference pressure arising above the edge of the array; σ ₀ is the level of natural stresses in the untouched massif; σ ₁ - the level of hazardous stresses in the array, when exceeded which there is a need for repair work in panel preparatory workings; X is the width of the zone of dangerous stresses arising above the edge of the mineral layer; l ₁ and l ₂ - the length of the lava, respectively, when mining the first and second pillars; NM - a section of the bypass working, located on the side of the untouched array; S is the minimum allowable distance between the panel preparatory workings 2, 3, 4 and the inner border of the first column (or, what is the same, the worked out space); Z is the distance between the precast preparatory workings 6 and 7.

The number of panel preparatory workings can be equal to 3, 2 or 1.

The method is as follows. Within the NBCLM mining site, the mining columns ABCLO and NALM are sequentially mined by a single lava. First, the first ABCLO column is mined with lava moving towards the boundary of the excavation site. When mining the first column of minerals ahead of the bottom of the lava pass: on the outer border of the mined excavation section bypass generation 1; panel 2, 3, 4 and local preparatory workings 5 and 6. Between the panel 2, 3, 4 and local preparatory workings 6, 7 are ovens 5.

One local preparatory development (7) runs along the inner boundary of the AO of the first column, the second reused local preparatory development 6, as well as panel preparatory workings 2.3.4 pass within the area occupied by the second column. When mining the first column (Fig. 1), the furnaces 5 pass ahead of the lava between the panel and local preparatory workings, while working out the second column (Fig. 2 and Fig. 3) of the furnace 5 pass between the panel preparatory workings and the bypass working 1. At the same time, the panel preparatory workings 2.3.4 pass at a distance S (Fig. 4) from the inner boundary of the first column, greater than the width of the zone of dangerous stresses X that occurs above the edge of the mineral layer. The distance between the precast preparatory workings is taken equal to the limiting width of the pillar located in the worked-out space, with a decrease in which the pillar is destroyed by rock pressure.

When bedding in the immediate roof of the mineral layer of strong stable rocks, the length of the lava l _{2 is} taken equal (Fig. 3) to the distance between the bypass working and the inner border of the first column.

When bedding in the immediate roof of the mineral layer of fractured unstable rocks, the length of the lava l _{2 is} taken (figure 2) equal to the distance between the reused precinct preparatory excavation and the NM section of the circumferential excavation located on the side of the untouched massif.

Justification of the materiality of the distinguishing features.

"... one precast development work pass along the inner border of the first pillar, the second preparatory work pass pass within the area occupied by the second pillar ..." and

"... the distance between the precast preparatory workings is taken equal to the limiting width of the pillar of a mineral located in a mined space, at the decrease of which the pillar is destroyed by rock pressure ..."

Carrying out two preparatory workings makes it possible: to form behind the lava during the mining of the first pillar a pillar of width Z, which is designed to increase stability and reduce the cost of maintaining the local preparatory workout 6, reused when working the second pillar; minimize the loss of minerals in the rear left between the local preparatory workings 6 and 7. When the distance Z between the local preparatory workings is equal to "... the maximum width of the pillar of the mineral ...", the technologically satisfactory state of the reused local preparatory workings 6 is ensured in during the entire period of its existence. The need to ensure the possibility of reuse of the local preparatory development 6 is associated with the creation of conditions for working out the second pillar with minimal losses. The presence of excavation 6 at the time of completion of mining of the first column allows (under ventilation conditions) to continue mining the excavation field without leaving a pillar of mineral between the panel workings and the first column. So, when mining the second column (figure 2), a fresh ventilation stream along the mine 1 enters the lava. It goes from the lava to the mine 6. Next, the spent jet can be issued from the excavation area by mine 6 or mine 6, 5, 4.

"... panel preparatory workings take place within the area occupied by the second column ..." and "... panel preparatory workings take place at a distance from the inner boundary of the first column, greater than the width of the zone of dangerous stresses arising above the edge of the mineral layer. .. "

The specified location of the panel preparatory workings 2, 3 and 4 allows you to minimize the cost of maintaining them throughout the life of their service. Achieving a positive effect is explained by the fact that from the time of the panel preparatory workings until they are paid off, they are maintained in the massif practically outside the zones of influence of treatment work and the marginal parts of the mineral massif.

"... when mining the first column of the furnace 5 pass ahead of the lava between the panel and local preparatory workings, when mining the second column of the furnace 5 pass between the panel preparatory workings and the bypass ..."

Conducting furnaces provides the ability to transport minerals from lava to panel preparatory workings designed to transport minerals (for example, a panel conveyor drift). So, when mining the first column (Fig. 1), the mineral within the excavation field after the lava is transported along the excavations 7, 5 and 3.

When mining the second column (figure 2 and figure 3), the mineral is transported along the workings 1, 5 and 3.

"... when solid stable rocks are located in the immediate roof of the mineral layer, the length of the lava is taken to be equal to the distance between the bypass working and the inner boundary of the first column ..." and "... when the fractured unstable rocks are located in the direct roof of the mineral layer of the bed, the length of the lava take equal to the distance between the reused precautionary mine and the bypass mine, located on the side of the untouched array ... "

These additional claims clarify the location of the lava relative to the bypass and preparatory workings for various geological conditions.

The implementation of these paragraphs can improve the efficiency of the proposed method by reducing the loss of minerals when occurring in the immediate roof of the mineral layer of durable stable rocks.

Compared with known methods, the inventive method of underground mining of mineral strata in areas of limited size allows: 20% or more to reduce the operational loss of mineral in pillars left within the excavation areas; several times reduce the cost of maintaining reused preparatory workings.

The parameters necessary for the implementation of the proposed method: - the width of the zone of dangerous stresses formed over the edge of the mineral layer;

- the value of the limiting width of the pillar located in the worked out space, with a decrease in which the pillar is destroyed by rock pressure.

The indicated parameters depend on the geological conditions of occurrence of the reservoir, are determined using well-known techniques as a result of mine, laboratory or analytical studies.

The field of rational use of the proposed method.

The inventive method is intended for use in underground mining of stratified mineral deposits (mainly salt and coal) with dip angles of seams up to 36 °. Using the proposed method in the conditions under consideration allows you to: reduce by 20% or more the loss of minerals and by 2-3 times reduce the cost of maintaining local preparatory workings.

An example of a specific use of the proposed method for the development of the 4th sylvinite layer of the Third potash layer in the mines of RUE PA Belaruskali.

The fourth sylvinite layer 1.3 m thick is mined at depths of 600-800 m from the surface. The angle of occurrence of potash salt deposits is 1-3 °. Depth of mining is 500-800 m.

In the conditions under consideration:

- the width of the zone of hazardous stresses forming above the edge of the mineral layer is 30-35 m;

- the maximum width of the pillar located in the worked out space, with a decrease in which the pillar is destroyed by rock pressure, is 4-5 m.

The lavas are equipped with modern mechanized treatment facilities, the optimal length of the extraction columns for which is 3.0-4.0 km. When using the known method for the development of the 4th sylvinite layer — the prototype (Auth. St. USSR No. 863860, Cl. E 21 C 41/04, Bulletin No. 34, 1981), the operational loss of minerals in the pillars left between the mined pillars reach 35% or more.

In the areas under consideration, the roof of the 4th sylvinite layer is represented by rocks with stable roof rocks. Therefore, for use, the adopted option presented in figure 1 and figure 3, providing for the development of a pillar of width Z between the precast preparatory workings 6 and 7.

The length of the lava l ₂ equal to the distance between the bypass excavation 1 and the edge of the massif AR (figure 3), is 170 m

For the preparation and development of the excavation section are: bypass excavation 1, panel transport drift 2, panel conveyor drift 3; panel ventilation drift 4, 5 - furnace; 6 and 7 - local preparatory workings. Generation 7, along with other functions (transportation of minerals, ventilation, movement of people), performs the function of unloading excavation for the local preparatory excavation 6 while maintaining it in front of the face of the lava working off the first pillar of ABCL.

The distance between the precast preparatory workings 6 and 7 is taken equal to 5 m.

Panel preparatory workings 2, 3 and 4 are passed at a distance S (Fig. 1 - Fig. 3) from the first column, equal to 35 m.

Using the proposed method in the considered mining and geological conditions allows: to reduce by 25-35% operational losses within the excavation areas compared with losses when using the known prototype method; almost completely eliminate repair work in panel preparatory workings 2,3 and 4 associated with the negative impact of treatment work on them.

Claims (3)

1. The method of underground mining of mineral deposits in areas of limited size, including the sequential mining of two columns of minerals with one lava, mining the first column of lava moving towards the boundary of the excavation section, drawing along the outer boundary of the excavation section of the bypass mine, conducting sectional and panel preparatory workings, conducting furnaces between panel and precast preparatory workings, turning the lava at the boundary of the excavation site with the settlement exploratory mining of the second pillar with lava in the opposite direction to the mining of the first pillar, characterized in that one precast development work pass along the inner border of the first pillar, the second reused precast workout, as well as panel preparatory workings pass within the area occupied by the second pillar , when mining the first pillar of the furnace pass ahead of the lava between the panel and local preparatory workings, when mining the second the forehead of the furnace passes between the panel preparatory workings and the bypass working out, while the panel preparatory workings pass at a distance from the inner boundary of the first column, greater than the width of the zone of dangerous stresses arising above the edge of the mineral layer, and the distance between the preparatory workings is taken equal to the maximum width of the pillar located in the worked-out space, the decrease of which causes the destruction of the pillar by rock pressure. 2. The method according to claim 1, characterized in that when bedding in the immediate roof of the mineral stratum of durable stable rocks, the length of the lava is taken equal to the distance between the bypass excavation and the inner boundary of the first column. 3. The method according to claim 1 or 2, characterized in that when the fracture of unstable rocks is located in the immediate roof of the mineral layer, the length of the lava is taken equal to the distance between the reused precast preparatory mine and the bypass mine located on the side of the untouched massif.

Images