Mechanized mining test of residual mine in a rock gold mine

In the 2015 World Mining Great Depression, depressed gold price (per ounce in 1056 dollars up and down) situation, China's gold industry is still adhere to large-scale production, since 2007, China's production of gold 270.49t since become a world superpower, continuous 8 The year was the leader. China's gold mines have several major characteristics: the development of geological grades is getting lower and lower, the national average is less than 2.5×10-6; the mining production capacity is getting larger and larger, generally more than 2000t/d; most enterprises can produce finished products. Gold; most mines have low earnings. For this reason, many mines now recycle large amounts of low
Grade residue.
A rock gold mine was developed in 1986. At present, the four mine sections of Yangshan, Wanjiawu, Shuizewu and Dawu are still in production. Due to the serious imbalance of the third-grade mines, the existing reserves are very much It is difficult to maintain normal production. In order to make full use of mineral resources, accelerate the end of the upper middle section, achieve the sustainable development goals, and carry out the development of the lower ore body. In 2009, the mine began to plan and purposefully recover the residual mines of the old system.

1 Overview of deposit development

The rock gold mine has undergone five renovation and expansion projects. At present, it has formed a production capacity of 2000t/d, with two new and old development systems.

The old development system consists of 118 inclined wells, 120 flat rafts, 147 inclined wells and Yangshan Hangkou. The 118 inclined wells serve 3 middle sections of 100, 75, 50m; 120 flat rafts mainly serve 120, 145, 162m3 middle sections; The well develops 50,25m2 middle section; the Yangshan mining section uses Pingyi to develop more than 110m ore body. The new system consists of main and auxiliary inclined shafts. It mainly develops ore bodies below 0m, serving the middle sections of 0, -40, -80, -105, -130, -155m, except for the middle section of -155m, which is still in prospecting. Middle section of production operations.
The surrounding rock of the ore body near the ore body is the Qiangyan rock, and the surrounding rock of the upper plate is mainly the weak star scattered and disseminated silicified sandstone and metamorphic Anshan basalt . The surrounding rock and the ore body have a gradual transition relationship; the structure, structure, mineral composition and mineral body of the carbon-bearing rock in the lower plate are quite different [1].
Mining is dominated by the room-column method or the comprehensive method, and multiple middle sections are simultaneously mined [2]. Most of the mines that have been mined in the past have formed goafs, leaving residual remnants such as corner remnants, top and bottom remnants and some supported primary pillars [3], including 7 intermediate sections of 25-162 m. The total geological reserves are grade 122b, reserves 452149t, grade 3.03×10-6, metal amount 1375.55kg, grade 333, reserves 623608t, grade 3.27×10-6, metal amount 2038.74kg.
2 trackless development design
In order to maximize the recovery of the residual ore, modern production methods are used, that is, the production is organized using trackless equipment. The recovery of residual ore was carried out in the middle section of 120 m. According to the actual situation of the mine, select the mechanized shovel equipment (Table 1), design the original main lane brushing and pressing top, and the main lane design specification is 4m×3.5m. Brush design range is 120m mouth (fragrant mushroom shed) ~ 323 line (10 line position), of which 300-311 line main lane brushing is divided into 2 roads, all the way is to design the main lane brush for the recovery of 303-311 line residual mine The other road is the main transportation roadway, which is the main transportation ore roadway of the 311 line and the 307 line concentrating funnel. There is also the design of the main lane diversion and yard. When the transportation vehicle turns, it cannot pass through the original lane of the main lane of 303-305 line. The main lane is designed to be re-routed from point A to point B. The minimum turning radius is designed to be 10m.
The track specification of trackless equipment is 120m in the middle section of Xinyikou to 307 line 4.5m×3.5m, the other main lanes are 4m×3.5m, and the wrong yard specifications are 10m×6m×3.5m. The design of the trackless transportation lane is shown in Figure 1. The design of the ramp for the transportation of trackless equipment is 3.6m×3.6m, the slope is -8°, the slope length is 448.4m, the roadway length is 133m, the total design length is 581.4m, and the radius of curvature of the curve is 10m according to the equipment model. The slope design is shown in Figure 2.

3 residual mine recovery test
3.1 Overview of test sites

The test stope is selected from the middle section of the 120m line -8~12. The -8～12 line ore body is approximately perpendicular to the exploration line in the space orientation, tending to NNE, the inclination angle is about 10°, the average thickness of the ore body is 6.2m, the total designed ore is 96400t, and the average grade is 1.89×10-6. The total amount of metal is 182.17kg.
3.2 Mining method selection
The designed back mining block has an average thickness of 8m, and the residual ore is stable. It should be recycled by the conventional shallow-eye room column method.
3.3 Cutting and cutting project layout and construction sequence
The mining and cutting project has adopted the approval of uphill, cutting lanes, pedestrian patios, slip mines, contact roads, electric ramps, mining and transportation routes, and fighting wells. 1# mining site first construction 1# mining on the mountain, then construction 2# mining on the mountain, the final construction 3# mining on the mountain, the design slope is 10 °; 2# mining site first construction 1# mining transportation approach brush, Re-construction 4# picking up the mountain, the last construction 1# cutting alley, the design slope is 10°; 3# stop first construction 2# mining transport approach, the second step construction 1# pedestrian patio, the third step Construction 1# slip mine and contact road, the fourth step construction 1#, 2# electric ramp, the fifth step construction bucket fight bucket well, the sixth step construction 2#, 3# cutting lane, the design slope is 20°; 4 #采场 first mining, no need to mine when a certain height, padding a layer of safety platform, while leaving a safe passage, then construction 3# electric roadway, and finally construction 5# pick up the mountain, the design slope is 17°.
3.4 recovery work
The 7505 and YT-29 hand-held horizontal air-leg rock drills are used to dig the horizontal or inclined blastholes. The upper mining should use the YSP-45 type upward boring machine to dig the vertical blastholes; the bottom layer height is 2~3m, the blasthole depth 2 to 3 m, the blasthole row spacing is 0.6 m, and the eye distance is 0.8 m.

Mine mineral explosives are used to blast mines. 1#, 2# stope uses scraper and car to mine, the original patio as a slip mine, install vibrating and concentrating machine; 3# stope mine to install vibrating and concentrating machine, ore directly loaded with car, no scraper; The 4# stope uses a scraper and a car to mine. Each mining point strictly controls the amount of ore.
When collecting on the shallow eye, the shape of the top plate should be strictly controlled to be arched. It is strictly forbidden to have unsafe phenomenon such as “falling belly”. If the fault or roof is unsafe during the mining process, the temporary anchor rod can be used for support.
There are many design space projects, and ventilation should be strengthened. Before the mining of the 2# stope, the upper empty area is used at the end of the 1# cutting roadway as the venting vent of the stope; the 3# stopway is ventilated through the 134m blind middle section, and the end of the 1# cutting lane is vertically through the upper empty area. ; 4# stope through 134m blind middle section ventilation. Strengthen the local mechanical ventilation during the construction process, maintain the proper ventilation time, arrange reasonable shifts, and unimpeded the return air passages [4].
3.5 empty area processing
The design leaves 17 3m×3m point columns to support the backspace [5]. The empty area formed by the backward mining will not enter the person, and the point column will be a permanent loss.
3.6 Technical and economic indicators
The mining of the quarry in the test site is strictly in accordance with the design plan, and all technical indicators have reached the design requirements, as shown in Table 2.

4 safety technical requirements
(1) Construction in strict accordance with the "Safety Regulations for Metallic Non-Metallic Underground Mines".
(2) Before the on-site operation, it is necessary to check the safety of the working surface and clean the pumice .
(3) Strictly implement the related safety technical measures such as the penetration of the project and the exploration of the air.
(4) Pressing and withdrawing mixed ventilation mode is adopted. If necessary, multi-stage local fan forced ventilation is arranged, and the required ventilation time requirement must be met to ensure the safe operation of the cannon smoke discharge and construction.
5 Conclusion
Residual mining is a mining problem that has been highly valued at home and abroad. Due to the complex state of the residual ore, it determines the diversity of its mining methods and it is difficult to standardize. A rock gold mine uses mechanized trackless equipment to efficiently recover residual ore, improve mine efficiency, ensure production safety, and achieve good economic and social benefits. The shallow-eye mechanized mining of the residual ore is only one of the methods for recovering the mine's residual ore, as well as the medium-deep hole empty field method and the conventional construction method. With the continuous development of mining methods and mining equipment, mechanized mining of residual ore will have broad application prospects.
references
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[5] Song Yongguo. Discussion on the recovery of residual ore in the Piaotang mining area [J]. China Tungsten Industry, 2003 (10): 32-34.