RU2233982C1 - Method for opening and processing deep horizons of kimberlite pipes - Google Patents

Abstract

FIELD: mining industry.

SUBSTANCE: method includes excavation of a quarry up to end contour, construction of quarry border walls at steep angles, freeze-protective covering of shelves slopes, processing of rocks, transporting of it by dump-trucks along the horizon, connected by ore chutes, cross-cuts to slanting spiral-like shaft. Cross-cuts pass from portions of maximum approach of spiral-like shaft to contour of ore body, in mouth portion of ore chute a special construction is formed for centering ore flows, for dump-trucks unloading, slopes of quarry border walls are planed by machines with working organs of rotor-cutting type, covered by freeze-protective gunite layer with variable thermal resistance and is fixed by anchors, processing of central portion of quarry horizons is performed by horizontal shelves, and periphery portions - by shelves slanted to side of quarry border wall, for forming special slanted safety benches.

EFFECT: higher effectiveness and safety of mining during excavation of deep horizons of deposits by open method under conditions of permafrost.

9 dwg, 1 ex, 8 tbl

Description

The invention relates to the mining industry and is created in relation to resource-saving and safe technologies for the development of deep-lying kimberlite pipes in extreme climatic conditions of the North.

There is a method of discovering mineral deposits during open cast mining, including conducting paired shafts with the placement of the mouths of the shafts in the upper worked part of the quarry field, horizontal workings and ore passes connected to the horizons of the quarry [1].

There is also known a method of opening deep horizons of a quarry, including pairwise holding of spiral inclined trunks with connecting their ends with a dead-end working and placing the outputs of underground workings to the horizons of the quarry after 5-8 steps along the working height [2].

However, both known methods are characterized by significant volumes of overburden production during the development of deep horizons and lack of efficiency.

There is a method of open mining of mineral deposits, in relation to limited in terms of deposits such as rod and tube, including the construction of a vertical closed lining along the contour of the quarry completion zone and the extraction of mineral from the circuit with a special lifting device [3].

This method is characterized by a limited scope, high costs and considerable complexity associated with the construction of fastening of the vertical sides of the quarry.

There is also known a method of forming an idle side of a quarry during the development of deep quarries under permafrost conditions, including the construction of ledges on the final contour of the quarry with slopes, which are coated with a heat-resistant coating of foamed plastics with a net cloth of synthetic material [4].

The disadvantage of this method is the low reliability of slope reinforcement, which leads to a decrease in mining safety during the formation of steep and high slopes, which, ultimately, cause the extraction of additional volumes of overburden production from the contour of the quarry being developed.

There is a method of dumping ore in the ore during opening and mining horizons in the upland pits, including a support cone-shaped element that excludes dynamic impacts on the receiving device of the outlet [5].

However, this method does not protect the side walls of the ore passage from damage caused by the collision of the ore pieces against its wall, starting from the wellhead (from the moment of dumping the dump truck) and along the trajectory of moving the ore pieces along the vertical channel of the ore discharge.

Closest to the invention, the technical essence is a method for stage-by-stage mining of deep kimberlite deposits, including quarrying to the final contour, detaching quarry sides at steep angles, frost protection of the escarpments of the ledges, mining of rocks, transportation by dump trucks along a horizon connected by ore passages, crossings with a slope spiral barrel [6].

The disadvantage of this method is the low efficiency and safety due to the destruction of the side walls of ore passages, the absence of special safety berms that protect mining equipment from possible rock outfall from the escarpment of ledges made up of permafrost.

The technical result of the invention is to increase the efficiency and safety of mining operations in the development of deep horizons of deposits by open pit in the conditions of permafrost.

This goal is achieved by the fact that according to the method of opening and working out the deep horizons of kimberlite pipes, including quarrying to the final contour, detaching quarry sides at steep angles, frost protection of the escarpments of the ledges, mining of rocks, transportation by dump trucks along a horizon connected by ore passages, crossings an inclined spiral-shaped trunk, new is that cross-sleeves pass from sections of the maximum approximation of the spiral-shaped trunk to the contour of the ore body, in A special centering ore flows is constructed for the unloading of dump trucks, the slopes of the quarry sides are planned by machines with executive bodies of the rotor-milling type, they are covered with permafrost sprayed concrete layer with variable thermal resistance and are anchored, the central parts of the quarry horizons are worked out by horizontal ledges, and - ledges, inclined towards the side of the quarry, forming a special inclined safety berm.

In the proposed method, new features in comparison with the prototype are:

- the use of a new type of ore pass with the construction of a special centering ore flow structure in the wellhead;

- use in the design of the steep side of the permafrost sprayed concrete layer with variable thermal resistance and fixing it on the slopes with anchors;

- the use of a combination of horizontal and inclined steps when working out the horizons of a quarry;

- the formation in the process of working out the horizons and detuning the idle side of the special safety berm accumulated towards the side of the quarry.

These new features eliminate the disadvantages of existing methods for mining deep kimberlite quarries and provides the following enhanced positive properties:

- the use of a new design of ore pass with a special device in its wellhead eliminates the destruction of the side walls of the ore pass during unloading of dump trucks due to the creation of a directed ore flow through the center of the ore pass and thereby significantly reduces operating costs during operation of the ore pass;

- the use of a new shotcrete slope coating with variable thermal resistance provides a uniform effect of ambient temperature on the exposed slope of permafrost and reduces the maximum load destroying the quarry side caused by uneven thawing of the slope of its side, which increases the efficiency of open cast mining;

- the technology of working out the horizons of the quarry by a combination of horizontal and inclined ledges allows you to create a special inclined safety berm with a reduced width to catch steep and high ledges falling from the slopes and, ultimately, to increase the safety of mining operations when working in mining transport equipment in the contour zone of the quarry.

The method is illustrated by drawings.

Figure 1 shows the plan of the quarry with the location of the underground workings; figure 2 is a transverse section of the quarry; figure 3 is a diagram of the ore; figure 4 is a diagram of the development of a quarry by a combination of horizontal and inclined ledges; figure 5 - the position of the idle side of the quarry at the end of mining; figure 6 is a diagram for calculating the width of the berm; 7 is a diagram of the thermal protection of the side of the quarry shotcrete layer.

The method is as follows.

The inclined shafts 2 and 3 extend from the side of the quarry 1 and the day surface (Fig. 1). Moreover, the inclined shaft 2 serves for dumping overburden by dump trucks from the quarry through spiral ramps 4 to the waste dump 5, and paired trunks 3 are respectively necessary for deep ventilation horizons and transportation of kimberlite ore to the beneficiation plant 6. As mining operations deepen, spiraling trunks 3 extend crosshairs 7, which serve as concentration horizons for transporting rocks from deep horizons Comrade deposits to the surface. To do this, between the horizons of the quarry and the concentration horizons, ore passes 8 are erected both for ventilation and for ore bypass (Fig. 2). Rocks from the horizons of the quarry by dump trucks 9 (Fig. 3) are tinkered with to the ore passes 8 located in the adit 10, and then through the crosshairs 7 and inclined trunks 3 equipped with conveyors, they move to the surface. In order to prevent the destruction of the side walls of the ore passage during unloading of dump trucks 9, the wellhead part 11 equips the ore stream-centering structure 12, which directs the ore stream 13 in the center of the ore discharge eliminating possible impacts of ore pieces against its wall.

The mining horizons of the quarry are a combination (figure 4) of horizontal 14 and inclined 15 ledges. The excavator 16 works off the central part of the horizon 17 with horizontal ledges 14, and the excavator 18 fulfills the peripheral section 19 with inclined ledges 15. In the process of working out the horizons along the height of the idle side, special safety burs 20 are formed, inclined towards the side of the quarry. These berms 20 are used to capture stones and objects accidentally falling from the spalls of the ledges, protecting mining equipment and people from possible negative consequences. After planning the slopes with special equipment, the spalls of the ledges are covered with a shotcrete layer 21 with variable thermal resistance 22 (Fig. 5). The quarry is being refined to depth with bottom parameters allowing the placement of mining equipment on it.

An example of a specific implementation of the method

The technical essence and advantages of the new technical solution are disclosed by the example of refinement of a deep-lying kimberlite pipe using underground workings and open work techniques in the zone of permafrost and extreme climatic conditions of the North.

The initial data for the calculations are as follows.

The depth of the existing quarry is 500 m, the depth of refinement of the quarry with new technology is 800 m, the diameter of the ore body is 200 m, the slope angle of the side of the existing quarry with a depth of 500 m is 45 °, the angle of the spall of the repayment ledge in the rework zone of the quarry with a depth of 300 m is 80 °, the recession ledge is 100 m high, the ore pass height is 100 m, the working ledge height is 15 m, the slope of the inclined ledge is 10%.

1. Determination of the main parameters of the quarry in the zone of its completion

The introduction of the new technology, first of all, will provide an increase in the slope angles of the side in the area of completion of the quarry at depths of 500-800 m. This will reduce significant volumes of overburden production.

An increase in slope angles will be achieved by reducing the size of the safety berms. With traditional technology, the width of the safety safety berm is averaged according to the following approximate formula and adjusted by the unified safety rules (EPB):

W _BT ≈ 1 / 3N _UP , (1)

where W _BT - the width of the safety berm with the traditional technology of detuning the sides of the quarry, m;

N _UP - the height of the redemption ledge, m

W _BT = _1/3 · 100 = 30 m.

Then the angle of slope of the side in the area of completion of the quarry with traditional technology will be (Fig.6):

ctgβ = N _UP · ctgα + P _B · W _BT / N _D = 3 100 ctg80 ° +2 30/300;

α = 67 ° 50 (2),

where α is the slope angle of the absorption step, deg;

β is the slope angle of the pit side, degrees;

N _D - the depth of completion of the quarry, m%;

p _b - the number of security berms.

According to the EPB, the dimensions of the safety berms in each case are refined by design calculations. In analogue [4], in order to reduce the width of the berm, a safety berm with a protective shaft is proposed for catching stones falling from the slopes of the ledges.

The recommended technology for flanking allows to reduce the width of the safety berm in comparison with the analogue due to the orientation of the slope towards the side of the quarry to reduce the trajectory and speed of the stones falling from the slopes of the ledges. According to the methodology (Roinishvili N.M. Protection of the railway line from mountain landslides and screes. - M.: Transport, 1973. - P. 233-237. - 304 p.) The value of the “rebound” of the stone falling from the escarpment in a collision with the site berm depends on the angle at which this collision occurs.

Calculations for the “popping up" of stones according to this methodology established the parameters of the safety berms with protective shafts with the existing technology for detuning the idle side (Fig. 6a). The calculation results are given in table 1.

W _BB = W _B + W _ZV ,

where W _BB - the total width of the security berm, m;

W _B - width of the safety berm, m;

W _ZV - the width of the protective shaft, m

Using the data of Table 1 at an absorption ledge height of 100 m and an inclination angle of 80 ° (see initial data), the width of the safety berm is determined by interpolation and it is 17.7 m (including the width of the protective shaft 4 m).

In the new technical solution, the protective shaft is absent, because it is compensated by the inclination of the safety berm. Therefore, the width of the new tilted berm will be equal (Fig.6 b),

LW = LW = W _B = 13.7 m.

Then the slope angles of the sides in the area of the completion of the quarry with the existing β _C and recommended β _P technologies are calculated using formula (2):

ctgβ c = 3 · 100 · ctg80 ° + 3 · 17.7 / 300,

α = 70 ° 40

ctgβ c = 3 · 100 · ctg80 ° + 3 · 17.7-H _B · ctg80 ° / 300,

α = 72 ° 40,

where N _B = 2 m - the height of the protective shaft, m

That is, the recommended technology for finalizing the open pit with an inclined safety berm allows increasing the slope angle of the pit side by 2 °.

A reduction in the volume of overburden operations in the quarry contour due to an increase in the slope angle of 2 ° is established using the relationships given in Table 2 (A. Androsov. Technology for the development of deep quarries in Yakutia. Novosibirsk: Nauka, 1996. - P. 65) .

With a pit depth of 800 m, the reduction in overburden volumes in the quarry contour V _K will be

V _K = 21.637 · 2 = 43.274 million m ³ ,

where 21.637 is the reduction in overburden volumes with an increase in the side inclination angle by 1 ° and a pit depth of 800 m.

2. Justification of the parameters and scope of work on the construction of underground utilities

As shown in figures 1, 2, 5, the opening of the horizons of the quarry with the new technology is carried out by paired inclined shafts at angles of 15 °, concentration crosshairs, ore passages and ventilation insurgents.

Underground conveyor and ventilation shafts in terms of the ore body represent logarithmic spirals described by the following mathematical expression [7],

where ρ is the polar radius, m;

τ _mp - the radius of the kimberlite pipe at the maximum depth of the quarry. m;

α _s - seismic safety distance from the limiting contour of the quarry to the conveyor barrel (according to the results of the VNIMI study α _s = 45 m);

k is the coefficient of proportionality;

φ are the current coordinates.

The practical implementation of such an underground communications scheme is achieved by forming it in the form of a broken spiral around a kimberlite pipe. The calculated values of the length of underground utilities are given in Tables 3 and 4.

Thus, the total length of underground utilities during the mining of a kimberlite pipe using the combined scheme was 10557.0 m, and with a margin of 5% it is 11084.0 m.

The volume of penetration of mining and development is respectively equal to 123089.0 m ³ and 129242.0 m ³ .

3. Calculations of the parameters of permafrost gunning concrete coating of slopes with variable thermal resistance

In contrast to the existing methods of thermal protection of quarry sides, we propose to apply a layer of shotcrete with a light filler, which simultaneously performs frost protection (reduces the depth of thawing of the slope of the quarry side of the quarry) and the fixing function at the same time (due to the formation of a hardened shotcrete layer). Moreover, a feature of the shotcrete layer is that along the length of the slope (from top to bottom) its thermal resistance is changed so as to achieve a minimum thawing depth at the top of the slope and maximum at the bottom, which ensures the stability of the thawed part of the array, forming a thaw profile in the form of a rectangle with a vertex at the top of the slope or in the form of a rectangular trapezoid with a permissible limited thawing depth at the top of the slope.

The essence of the method is illustrated by the drawings presented in Fig.7. On figa shows a method of attaching the slope 1 shotcrete layer 2 with constant thermal resistance R _T - const. In this case, a thawing halo is formed with a depth of 3. If the weight of the rocks in zone 4 exceeds the shear strength of the rocks and the coating strength is insufficient, then a landslide along slip line 5 will occur and the quarry slope will be destroyed, i.e. an emergency is created. To avoid this, it is proposed to arrange a permafrost coating with variable thermal resistance so that the thawing depth in the upper part of the slope is minimal and maximum in the lower, and the weight of thawed rocks in no section exceeds the permissible shear load. By forming the depth profile of thawing rocks in this way, we increase the stability of the slope of the pit side and ensure its trouble-free operation. On figb presents an element of the side of the quarry with a coating of 2, the thermal resistance of which is variable along the length of the slope L: R _T = f (1) (where L is the length of the slope). Line 3 shows the depth of thawing of the rocks. In this case, the total weight of thawed rocks per unit area at the bottom of the slope does not exceed the load at which the shift of rocks occurs. In this case, we believe that the strength of the coating itself, which also performs a supporting function, goes to the estimated margin. The thermal resistance of the coating can vary both by changing the thickness of the coating and by changing the concentration of the porous filler. Consider a specific example of the method. We have a vertical slope of 15.0 m in length. With a thawing depth of 1 m and a density of thawed rocks of 1,500 kg / m ^{3, the} weight of a column of thawed rocks will be 22,500 kg per 1 m.

The load at which a shift of 1 kg of thawed rocks occurs is equal to 14,000 kg / m ² . Then a possible expected rock shift can occur at a height:

14000 = 1 · 1 · 1500h _pr

or

h _ol = 14000/1500 = 9.3 m.

Now, under the same conditions, we consider the case of using variable thermal resistance. At the top of the slope, the thawing halo is zero, at the bottom - 1 m. The total weight of the melt zone rocks

· ¹⁵ January _1500/2 = 11250 kg / m ²

Therefore, since 11250 <14000, the destruction of the side will not occur.

By the reverse calculation with the known strength characteristics of the rocks, the permissible thawing depth at the bottom of the ledge can be calculated and the thermal resistance and strength of the shotcrete coating can be calculated.

4. The rationale for the stability of the steep sides of quarries

Justification of the stability of the sides of the quarry is reduced to determining its safety margin. Assessment of the stability coefficients in the traditional and recommended detuning options was carried out according to the well-known methodology (Yu.P. Astafiev, R.P. Popov, Yu.M. Nikolashin. Management of rock mass in opencast mining of mineral deposits. -Kiev-Donetsk: Publishing House High School, 1986, pp. 21-31, pp. 124-132).

In the illustrated example, using traditional technology, the side of a quarry with a height of 180 m is built up with 30-meter recession ledges with vertical (90 °) angles (the Udachny open pit reconstruction project) and the corresponding safety berms are left every 30 m. In the recommended embodiment, the sideboard with a height of 180 m is built up with two recession steps, the height of each step is 90 m. The slope angles of the sides, respectively, with the traditional and recommended methods, were 70 ° 40 'and 72 ° 40' (see §1).

The calculations were performed with the following parameters of the physical and mechanical properties of the rocks:

s - coefficient of adhesion of rocks, s = 48 t / m;

γ is the bulk density of the rocks, γ = 2.59 t / m;

φ is the angle of internal friction of the rocks, φ = 30 °.

The sequence of calculations is constructed as follows.

A. Determine the vertical separation gap h ₉₀ ,

B. According to the calculated characteristics of the rock resistance to shear, we establish the width of the prism of possible collapse α, respectively, with the existing α _c and recommended α _p technologies:

Substituting the corresponding values of β _c and β _p , we find α _s and α _p at H = 180 m, α _c = 64.45, α _p = 70.55 m.

B. Build the sliding surface of the quarry side (the prism of possible collapse) and divide the area of possible collapse into blocks, in this case, 10 blocks.

D. We calculate for each i-th block shear forces F _{cdv i} , friction forces F _{tp i} and adhesion forces F _{sc i}

To do this, first we calculate the mass of each block P _i (gravity),

where in - the width of the block, m;

h - block height, m.

where β is the angle of inclination of the base of the block, degrees, B = 60 °.

F _Tr = N · tgφ,

where N is the normal force, t.

N = p cosβ

F _sc = c · L,

where L is the length of the slip line in the block, m

We calculate the force data for each block, and then summarize:

D. We determine the safety factor n as a ratio,

Table 5 for the existing method shows the results of calculations of the values of shear forces, friction and adhesion according to the method described.

Then the safety margin of the board with the existing method will be:

Similar calculations were performed for the recommended option and the safety factor n _p amounted to:

n _p = 1.53.

That is, the recommended option allows you to increase the safety margin of the pit side by 1.3 times and thereby increase the safety of mining during mining of deep horizons.

5. The rationale for improving the operating conditions of ore passes

In the calculations of the kinematics of the falling pieces of ore along the ore pass, it is assumed that the pieces of rock mass have the shape of a ball, and the walls of the ore pass are accepted smooth. Moreover, the path of movement of the falling piece can be divided into the following sections [7]:

1) the unloading area (from the dump truck to the first collision);

2) the first section of the fall;

3) the second section of the fall, etc.

For the portion of the unloading acceleration of the piece U _p is determined by the following formula:

U _p = g (sinα _a -f _k cosα _a ), m / s ² ,

where g is the acceleration of gravity, m / s ² ;

α _a - the tilt angle of the body of the truck to the horizon, deg .;

f _k = 0.53 - coefficient of friction.

U _p = 9.8 (0.96-0.53 · 0.26) = 8.03 m / s ² .

The speed of the piece in the discharge section V _p will be:

where L _k - unloading length, m, (L _k = 4,5 m)

V _p = 6.01 m / s

The horizontal component of the speed of the piece

V _1x = V _p cosα _a = 6.01 · 0.26 = 1.56 m / s

The vertical component of the speed of the piece

V _1y V _p sinα + gt ₁ ,

where t ₁ - the time the piece falls to the first section, s.

where D _p is the diameter of the ore pass, m (D _p = 3 m)

V _1y = 6.01 · 0.96 + 9.8 · 1.92 = 24.58 m / s

The depth of the first collision of the piece with the ore wall with the recommended method is calculated by the formula:

where C _y = 0.4 m is the distance from the lower edge of the dump truck body to the mouth of the ore pass, m

The speed of the piece in the first section is determined by the formula:

After the collision of a piece with the ore wall, according to the theory, the horizontal component of the initial velocity will be equal to:

V _2x = k _a · V _1x = 0.75 · 1.56 = 1.17 m / s,

where k _in - coefficient of recovery upon impact, varying from 0 to 1 (for rocks k _in = 0.75)

Vertical component of speed and fall time:

V _2y = V _1y = 24.58 m / s,

t ₂ = t ₁ / k $\genfrac{}{}{0ex}{}{\text{2}}{\text{in}}$ = 1.92 / 0.56 = 3.43 s

The height of the second section of the collision of the piece is

h ₂ = V ₁ · t ₁ / k + gt _into $\genfrac{}{}{0ex}{}{\text{2}}{\text{1}}$ / 2k $\genfrac{}{}{0ex}{}{\text{2}}{\text{in}}$ -C _y = 94.9 m

where C _y = 0.4 is the distance from the lower edge of the body of the truck in a raised state to the mouth of the ore pass, m

Thus, at an ore depth of 100 m using a new technical solution, a piece strikes the ore wall of the ore only 1 time in the discharge section with a depth of 20.6 m, and the next impact occurs at the bottom of the ore passage (Table 6).

Using the similar formulas, the trajectory of the falling piece of ore along the ore pass is calculated using the traditional method of dumping dump trucks. The calculation results are summarized in table 7.

From table 7 it is seen that when unloading dump trucks according to the traditional scheme, i.e. without a special centering ore flow structure, the impact of pieces of ore on the wall of the ore pass with a depth of 100 m occurs 4 times, respectively, at depths of 1 m; 14.5 m; 21.57m; 49.4m

It follows that with the recommended new technology of exploitation of ore passages, their service life is increased up to 2.5 times.

6. The expected improvement of technical and economic indicators from the introduction of a new method

Improvement of technical and economic development indicators from the introduction of a new method of opening and mining deep horizons of kimberlite pipes is achieved by:

1) increasing the angles of slopes of the sides in the area of completion of quarries;

2) reduction in the volume of stripping operations in the open-cast mining circuit;

3) reduction in the volume of mining and development workings;

4) increase the life of ore passes and reduce the cost of their operation;

5) improving the safety of mining operations when mining deep horizons of deposits.

As a basic option, the option of finalizing the quarry of traditional technology without the use of special structures of the quarry sides using spiral underground workings (V.M. Vlasov, A.D. Androsov. Using underground workings in diamond mining quarries of Yakutia // Gorny Vestnik. - 1997. - No. 6. - S.64-66).

As a result of improvements in the design of open pit walls and ore passes, an increase in the slope angles of the sides, a reduction in the life of ore passes and a reduction in the cost of their operation have been achieved. Due to the rational arrangement of cross-barrels in relation to the ore body, the volumes of sinking of mining preparatory workings (cross-barrels) are reduced, and the increase in the safety of mining is ensured by covering the slopes with a special permafrost protective shotcrete layer with variable thermal resistance and anchoring. This design of the coating eliminates the accidental fall of stones from the slopes of high and steep ledges, protecting people and equipment from the tragic consequences.

Table 8 shows the results of calculations of the social and economic effects of the introduction of the new method.

In calculations of economic efficiency, the prime cost of developing 1 m ³ of rocks was adopted as average for ALROSA and equals $ 3.41 / m ³ . The costs of driving underground cross-ditches are calculated using the literature [7] taking into account the cost increase coefficient of the cost of sinking 1 p.m. crossbar for conditions of the Far North, equal to 2.5. The reduction in cross-digging volumes due to their rational arrangement with respect to the ore body is 43%.

Thus, according to the calculations, the introduction of a new technical solution will provide savings of $ 148.3 million when mining kimberlite pipes in the depth range of 500-800 m. In addition, the implementation of the technical solution in the conditions of an existing enterprise will bring a social effect of reducing accident rate by increasing the stability of the quarry sides, the reliability of operation and the standing time of ore passes.

Sources of information

1. USSR author's certificate No. 717335, cl. E 21 C 41/00. The method of opening mineral deposits in open pit mining. - 1980.

2. USSR author's certificate No. 694640, cl. E 21 C 41/00. The method of opening the deep horizons of the quarry. - 1979.

3. Copyright certificate of the USSR No. 875041, cl. E 21 C 41/00. The method of open development of mineral deposits. - 1981.

4. Patent of Russia No. 2034150, cl. E 21 C 41/26. The method of forming a non-working side of the quarry. - 1995.

5. Abeghyan Ts.Kh., Mkrtchyan B.I., Sargsyan E.S. et al. Improving the efficiency of exploitation of ore passes in upland quarries // Mining Journal. - 1991. - No. 3. -FROM. 19-21.

6. Patent of Russia No. 1819330, cl. E 21 C 41/00. The method of stepless mining of deep kimberlite deposits. - 1990.

7. Shchelkanov V.A. Underground workings in quarries. - M .: Nedra, 1982. -128 p.

Claims (1)

The method of opening and working out the deep horizons of kimberlite pipes, including working out the quarry to the final contour, adjusting the sides of the quarry at steep angles, frost protection of the escarpments of the ledges, working out rocks, transporting it with dump trucks along a horizon connected by ore passages, crosshairs with an inclined spiral trunk, different that the crosshairs pass from the areas of maximum approximation of the spiral-shaped trunk to the contour of the ore body, a special center is being built in the mouth of the ore pass The ore flow-generating structure for dumping dump trucks, slopes of open pit mines are planned by machines with rotary-milling-type actuators, they are covered with permafrost sprayed concrete layer with variable thermal resistance and secured with anchors, the central part of the open pit horizons are worked out with horizontal ledges, and peripheral sections with ledges inclined into side of the quarry, forming a special inclined safety berm.

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