Evaluation of the collapse method with bottom column

(1) Main advantages

(1) Adaptability is strong, the program is flexible, and the fall plan can also be changed due to the characteristics of the rock.

(2) It can make full use of the existing equipment in the country, and work in mining, cutting and falling mine lanes with high work efficiency and high strength. Using electrical equipment out of mine rake, rake a road production capacity of up to 200 to 300 tons / Taiwan. Day (such as in the mountains of non-ferrous metal rake mine coal mine company's ability to build sub 759 middle 105 mining has reached 600 tons / Taiwan. day). Another example is a copper ore easy to use with a door pillar sublevel caving, the average rate of decline of up to 32 m, typically 22 to 27 meters. )

(3) High labor productivity. The comprehensive work efficiency including mining, cutting, support and mining, mining, etc. is 15 to 23 tons / I. tons.

(4) Low mining costs. How to reduce the cost of the North Copper Mine is 1.422 yuan / ton.

(5) Once the amount of mine collapse, the amount of deposits and deposits is large, and production is active.

( 6) Good ventilation and excellent working conditions.

(ii) Major shortcomings

(1) The amount of mining and cutting engineering is large. The structure of the stope is complicated and the mechanization of the construction is low.

(2) Ore loss and depletion are relatively large. Especially when the mining conditions are poor and the management is not good, the losses and depletion are more serious. (According to the 1981 survey data, the loss rate is generally 15 to 25%, and the depletion rate is generally 20 to 30%.

(3) It is difficult to increase the level of mechanization at the upper level.

(4) Generally, the stone cannot be removed, and the distribution cannot be separated.

(5) Management work is more complicated.

(3) Redirection direction

(1) It should be studied how to reduce the amount of mining and cutting, simplify the structure of the stope, and improve the level of mechanization, especially the mechanization of horizontal construction.

( 2) Strengthen the management of release and reduce the depletion of ore losses.

(3) Further promote the use of extrusion blasting and conduct further research.

(4) Pay attention to the observation and research of ground pressure and rock movement.

(5) Improve the efficiency of mining. For example, most of the mines currently use electric shovel to mine, and the main reasons affecting the efficiency of shovel mining are high bulk rate, long secondary crushing time and short lead smelting time.

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