Coil Slitting Line,Slitting Line For Sale,Cut To Length Line For Sale,Steel Cut To Length Machine JINAN RAINTECH MACHINERY INDUSTRIES CO.,LTD , https://www.rollformingindustry.com
Evaluation of sublevel caving method without bottom pillar
(1) Applicable conditions
(1) The surface and surrounding rock are allowed to collapse;
(2) The ore is stable and does not require a large amount of support. However, with the development of support technology, the requirements for the stability of the ore are reduced, and the stability of the surrounding rock is not limited, but the surrounding rock is prone to collapse. The method is more advantageous.
(3) The ore is not very expensive, has good selectivity, or the surrounding rock contains grades, allowing for a larger depletion rate. (Generally not suitable for the extraction of precious metals or high-grade ore body)
(4) A steeply thick ore body or a gently inclined ore body.
(5) The ore needs to be stripped of stone or graded ore.
(Temple of iron ore, Fushan iron ore, iron ore and other broadly in line with Huashugou use Sublevel caving).
(ii) Main advantages:
This method is a highly efficient mining method. It was developed with the advent of trackless self-propelled and shipping equipment.
(1) The safety is good, all the mining work is carried out in the mining roadway. There is no working space with large exposed surface. The section of the mining outlet is large, which is not easy to block, which reduces the difficulty and danger of handling the blockage and is beneficial to improve the mining. strength.
(2) Simple tillage, no pillars, one-step recovery, no recovery of the pillars, and no complicated bottom structure.
(3) The acquisition and recovery processes are simple and can be standardized, making it easy to use high-efficiency mechanized equipment. The same type of equipment can be used for picking and mining.
(4) The mining workload is small, and the mining coefficient is about 5 to 10 m/kT. (Because the section of the mining roadway is large and open in the vein, more ore is paid for the mining, and the amount of ore produced is about 10 ～20%, while the grade of ore produced is high.)
(5) There are many working faces, concentrated production, high recovery intensity and convenient management.
(6) Mining, rock drilling and mining can be carried out simultaneously on different sections without interference.
(7) This method is flexible, easy to remove stone, or graded ore,
(8) Exploration is easy to combine.
(3) Main disadvantages:
1. Poor ventilation conditions. There is no local fan ventilation in the ore blocks of most mines in China, mainly relying on the main airflow diffusion ventilation, the system is incomplete, the measures are not suitable for poor air quality, the dust concentration is large, and the production technology management is poor.
2, the mining is behind the mining, the reason is that the mining efficiency is low, the low reason is the driver's low level of operation technology, large loss of measuring parts, low starting rate. The equipment itself is not very capable, (foreign dumpers with large buckets, electric crab claw loaders with diesel-powered self-propelled cars, mining).
3, ore loss, depletion, the ore loss rate is generally 20-30%, depleted 15-20%, loss rate as high as 43% and depleted as high as 42.9%.
The main reasons for the poorness are:
1 the reason for the bottomless column collapse method itself;
2 Improper use of this method; (Some mines are originally gently inclined ore bodies are also mined using a bottomless column method).
3 The selection of method structure and structural parameters is not reasonable enough, and production management is not good.
(iv) Improving direction
(1) Study the new stope structure form and its reasonable mining method structural parameters, improve mining intensity, reduce ore loss and depletion, and fundamentally change the ventilation conditions.
(2) Study some auxiliary machinery and equipment that reduce the loss of losses.
(3) Research advanced detection methods (such as testing instruments for cutting out grades, etc.).
(4) To study the production of high-efficiency, low-pollution or non-polluting mining, loading machinery and auxiliary equipment suitable for the use of pillarless sublevel caving mines in China, and to equip these equipments to achieve a real economy. effect.