(1) Overview. The mine is located 161km southwest of Denver, Colorado, USA. There are 2,800 employees, and the daily output of ore is 42,660 tons, of which two underground mining levels are 27,230 tons of ore, and an open-pit mine has a daily output of 15,430 tons.
The Klemaks deposit consists of a large-scale reticular vein of the Tertiary immersed in Precambrian granite and schist. Molybdenum minerals are produced in cracks formed by immersion. The ore body shape and size are shown in Table 1. The collapse characteristics of the ore body are shown in Table 2.
Table 1 Technical conditions for mining of natural caving method in foreign application stage
country | Mine name | Mining method | Deposit type | Ore body morphology | Ore inclination |
United States | Clemex Molybdenum Mine (Climax) | Overall continuous collapse, embers mining | Reticulated vein molybdenite | The section is in the shape of a circle, and the plane is oval. | |
United States | Henderson Copper Molybdenum Mine (Henderson) | Overall continuous collapse, scraper mining | Reticulated vein molybdenite | The cross section is serpentine and the plane is elliptical | |
United States | Longrad Molybdenum Mine | Continuously falling all day, electric shovel mining | Reticulated vein molybdenite | Oval vertical column | |
United States | Questa Molybdenum Mine | The mass of the nugget collapses | Molybdenite | Horizontal tubular | |
United States | St. Manuel Copper Mine | The mass of the nugget collapses | Dip-like porphyry copper-molybdenum ore | The section is inclined U-shaped and the plane is semi-elliptical | The southern ore body is steep, and the northern ore body is about 50°. |
United States | Grace iron ore | Overall continuous collapse, scraper mining | Massive magnetite | Waist shape | 30° |
Chile | Eltnent Copper Mine | The ore collapsed, the grid sieved out of gravity (secondary mine); the panel collapsed, the scraper demineralized (primary mine) | Massive sulfide copper ore | Columnar | steep |
Chile | El Salvador Copper Mine | The mass of the ore collapses the grid gravity, the embers and the scraper mine | Porphyry copper deposit | steep | |
Canada | Satford Asbestos Mine | The nugget collapses and the scraper mines | Igneous network asbestos vein | The plane is oval | steep |
Philippines | St. Thomas Copper Mine | Nugget collapse | Dip-dyed brass deposit | The section is tubular and the plane is oval | 80° |
South Africa | Dipie Diamond Mine | Panel collapses, embers are mined | With diamond brecciated mica |
Unfinished, see continued table 1 [next]
Continued Table 1
country | Mine name | Ore body size (m) | Ore body caving characteristics | ||||
Go | thickness | Vertical height | RQD (%) | Joint density (bars / meter) | Compressive strength (MPa) | ||
United States | Clemex Molybdenum Mine (Climax) | 1219 | 250 | 420 | 40~70 | 8~11 | 34.3~109.8 |
United States | Henderson Copper Molybdenum Mine (Henderson) | 914 | 671 | 185 | 47 | 6.6 | 123.6~130.4 |
United States | Longrad Molybdenum Mine | 360 | 120 | 300 | 50 | 3 | 117.7~127.5 |
United States | Questa Molybdenum Mine | 1524 | 122~244 | 122~244 | 15 | >100 | weak |
United States | St. Manuel Copper Mine | 1500 | 30~300 | 600 | 30~40 | 13 | 98.1~132.4 |
United States | Grace Iron Mine | 360 | 90 | From very broken to very strong | |||
Chile | Eltnent Copper Mine | 1800 | 400~700 | 700 | 0~50 70~100 | 15~90 0.5~3 | 98.1~117.7 |
Chile | El Salvador Copper Mine | 1370 | 914 | 50~213 | From very weak to very strong | ||
Canada | Satford Asbestos Mine | 457 | 244 | 366 | 59 | ||
Philippines | St. Thomas Copper Mine | 330 | 210 | 1000 | Good caving and fracture | ||
South Africa | Dipie Diamond Mine | 900 | 450 | 175 | |||
Table 2 Rock fragmentation characteristics of some mines in the natural caving method at the domestic and international application stages
Mine name | Number of joint groups | Joint density (bars / meter) | Complete rock block compressive strength (MPa) | RQD (%) | Cavitation index | Initial pull-down area (m 2 ) | Original rock stress (MPa) | Capacitability description | |
Level | vertical | ||||||||
Jurad Molybdenum Mine | 3 sets of steep joints without horizontal joints | 3 | 117.7~127.5 | 50 | 7.5~8 | 14214 | 10.0 | 18.0 | Difficult to collapse |
Clemex molybdenum mine | More than 3 sets of joints have horizontal joints | 8~11 | 34.3~109.8 | 47~70 | 3~5 | 122×122 | 7.0~8.0 | 11.0~13.0 | Easy to medium collapse |
Henderson Copper Molybdenum Mine | 2 sets of steep joint level joints are not obvious | 6.6 | 123.6~130.4 | 47 | 6 | 120×180 | 29.0 | 30.0 | Medium collapse |
St. Manuel Copper Mine (San Manuel) | 3~4 sets of joints have horizontal joints | 13 | 98.1~132.4 | 30~40 | 5~6 | 40×60 | 140.0 | 112.1 | Easy to collapse |
Eltnient Copper Mine (primary mine) (El Teniente) | 2 groups of steep joint levels are not developed | 0.5 | 98.1~117.7 | 70~100 | 7~10 | 40.0 | 39.0 | Hard to collapse | |
Lakeside Copper Mine (Lakeshore) | Extremely developed | 25.6 | 2.0~147.1 | 15 | 3~4 | 30×30 | 7.0 | 6.0 | Easy to collapse |
Zhongtiaoshan Nonferrous Metals Co., Ltd. | 2 sets of steep joint level joints are not developed | 6 | 73.5~147.1 | 70 | 7~9 | 120×133 | 11.8 | 4.9~5.9 | Collapse |
(2) Appropriate layout. The stage height is 91.4m. The circular transportation system is used to transport the roadway through the veins, and the distance between the tunnels is 61m. A return air duct is tunneled in the middle of the two tunnels and connected to the main return duct below the transport level through the return air patio (see Figure 1). Excavation of pit wood and explosive storage chambers in the tunnels, each of which serves four electric roadways. A power distribution chamber is installed in the two electric roadways. There is a pedestrian well in each electric roadway. Excavation in the upper and lower rock in the vein transport lanes and part of the vein transport lanes using resin or mortar anchors, or bolts and metal mesh joint support, the other mining lanes are supported by integral watering concrete.
Figure 1 eDonkey mining
1-total return air duct; 2-transport lane; 3-return lane; 4-electric roadway;
5-lower roadway; 6-pullhole blasthole; 7-return air patio; 8-return well; 9-personal well [next]
Arrangement and support of the eluene mining system. The electric roadway is arranged at the level of the top plate of the tunnel, and its arrangement is shown in Figure 1. The distance between the electric roadway is 20.8m, the length is 34.1m, and the upward slope is 5%. The watering concrete is divided into three sections (winning chamber, loading port and ramp) for support. The thickness of the concrete is 300mm. When the floor of the roadway is poured, a 27.2kg steel rail is buried to enhance its wear resistance. The net width of the electric roadway should be 300mm larger than the width of the bucket used to improve the filling factor of the bucket. A ф-0.6m return air well is connected to the lower return airway at the end of the electric roadway. Each electric roadway is arranged with symmetrical three pairs of finger-shaped patios with a spacing of 9 to 12.8 m. The finger-shaped patio is at an angle of 45° to the horizontal and 6.4 m long. Among them, 4.57 m is supported by concrete, and the net section is 1.37×2.44 m. Then, dig a 2.44 m high vertical patio from the top of the finger patio to the bottom level. In the order of deep bottom blasting, the vertical patio at the bottom is expanded into a bell mouth.
(3) Pulling the bottom. Dig the bottom roadway in the 8.2m parallel electric roadway above the floor of the electric roadway. A fan-shaped blasthole is drilled in the bottom roadway, with a hole depth of 4.6 to 11.3 m and a row spacing of 1.5 m. Each row of roadway blasts 3 rows of fan-shaped blastholes. In order to avoid the high-stress concentration of the lower part of the high-stress concentration caused by the collapse line, the blasting of the bottom roadway in the middle part of the ore body is advanced, and 2 to 5 rows of blastholes are delayed from the middle to the bottom of each roadway. Form a pull-up push line similar to a skull.
(4) The border is weakened. Dig into the patio every 30m along the boundary of the upper and lower ore bodies, tunneling two layers of weakened roadway between the patios, drilling a single row of vertical deep holes up and down along the weakened roadway, with a hole diameter of 76mm and a hole spacing of 1.5m. . The pre-cracking height depends on the collapsibility, from 10m to 45m.
(5) Electric roadway support. The electric roadway is supported by poured concrete, and the concrete is transported by trains consisting of two 4.6m 3 concrete tankers (with agitation) and an 8t electric car. There are two such concrete tankers that travel between the concrete mixing plant and the work site. The concrete is wet-transported and has a label number of 350 and is pumped into the formwork. The templates used are prefabricated reusable metal templates and wood templates that are custom made to order. The amount of concrete in an electric roadway is 306m 3 , and the amount of three pairs of finger-shaped patios is 160m 3 .
(6) Mine control. Yankuang uses a 111.75kw double-drum series electric pick-up winch with a 1.8m wide folding bucket, which can mine 2.27t at a time. To prevent the head rope or tail rope from breaking back, use a 32mm pre-stretched (used) wire rope.
The ore contact surface is positioned at an angle of 45°. The discharge funnel near the bottom line is only allowed to release up to 10% of its ore. The allowable ore discharge percentage of the discharge ore funnel located at the end of the discharge line is 90-100%, and the allowable ore-mining percentage of each row of funnels increases by 10%. Thus, when the spacing of the ore hopper is about 10 m and the height of the caving ore column is 91 m, the width of the effective ore-mining area should be kept above 91 m. There are 210 electric roadways in this area, and 60 to 70% of them are generally mined. The average ore-mining speed of the ore hopper is 0.3m/d, the ore-mining speed of the ore in the process of caving is not more than 0.15m/d, and the ore-mining part under the cover rock is about 0.6m/d. [next]
The main technical and economic indicators are shown in Table 3.
Table 3 Main technical and economic indicators of natural caving method in foreign mine application stage
Mine name | Production scale (t/d) | Labor productivity (ton / work class) | Secondary crushing explosive unit consumption (kg/t) | Ore recovery rate (%) | Ore depletion rate (%) | |
Underground production workers | Full mine | |||||
Klemax Molybdenum Mine Henderson Copper Molybdenum Mine Questa Molybdenum Mine St. Manuel Copper Mine Grace Iron Mine Eltnient Copper Mine (Secondary Mine) El Salvador Copper Mine Satford Asbestos Mine St. Thomas Copper Mine Dipie Diamond Mine | 48000 28000 13600 55000 10000 62000 26000 4080 21000 5.3 million tons / year | 200 58.7 34~45.3 73 72 54.67 twenty four | 31 31.8 17 36 45 17~20 14 6.5 | 0.23 0.023 0.454 0.01 0.272 0.249 0.09 | 92.5 96 97 101.5~134.4 85 90.95 100 100 | 15 15 20 12.2~14 20 10~20 20 20 |
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