Inventory of Metal Ore Mining Methods

The metal mining method is to study the mining method of ore blocks. It includes three tasks: mining, cutting and mining. The sum of the mining, cutting and mining work performed in the mineral blocks in order to better recover the ore is called Mining methods. The main mining methods currently used are: open site mining, backfill mining, and caving mining.

1. Open field mining method:

During the mining process of the open pit mining method, the ore block is divided into ore rooms and ore pillars. The room is mined first, and then the pillars are mined. The basic conditions for applying open-site mining method are that the ore and surrounding rock are stable, and the goaf area is allowed to have a large exposed area within a certain period of time. Among them, the most widely used mining methods are: comprehensive mining method, room and pillar mining method, ore retention mining method, staged mine house method and staged mine house method.

(1) Comprehensive mining law. Comprehensive mining methods are applied in gently inclined (inclination angles generally less than 30°) ore bodies where thin and medium-thick ores and surrounding rocks are stable. Its characteristics are: the working face is fully advanced along the direction or tendency of the ore body. During the mining process, the rocks or poor ore in the ore body are left behind, forming irregular ore pillars to protect the goaf. These ore pillars are generally used as Permanent loss, no recovery.

(2) Room and pillar mining method. It is used to mine horizontal or inclined ore bodies. The ore rooms and ore pillars are placed alternately in the ore block or goaf area. When returning to the mining room, continuous or intermittent regular ore pillars are left to protect the top rock. It has a wider application range than the comprehensive mining method and can mine not only thin ore bodies, but also thick and extremely thick ore bodies. The basic conditions for the application of this mining method are that the ore and surrounding rock are stable horizontal and gently sloping ore bodies.

(3) Mine retention mining method. Workers work directly on the ore piles under the exposed surface of the mine house, mining in layers from bottom to top. About 1/3 of the ore mined each time is released by its own weight, and the rest is temporarily kept in the mine house for continued mining. tower. After all the mining in the ore house is completed, the ore temporarily left in the ore house will be released in large quantities, that is, large-scale ore extraction. This mining method is suitable for mining steeply inclined deposits where the ore and surrounding rock are stable, the ore is non-spontaneous, and is prone to re-agglomeration after crushing.

(4) Phased mine house method. According to the vertical direction of the ore block, it is further divided into several sections. The ore room and ore pillars are arranged horizontally in each section. The ore mined in the middle section is transported out of the ore tunnel of each section. After the mining of the sectioned mine room is completed, the ore pillars of this section can be mined immediately and the goaf area can be processed at the same time.

(5) Stage mine method. The open-site mining method using deep holes to return to the mining room can be divided into the horizontal deep hole stage mine room method and the vertical deep hole stage mine room method according to the different ways of falling ore. The former requires bottom pulling at the bottom of the mine house, while the latter requires, in addition to bottom pulling, vertical cutting grooves across the entire height of the mine house.

2. Caving mining method:

The caving mining method is a mining method that uses caving surrounding rock to achieve ground pressure management. That is, as the ore collapses, forced (or natural) caving surrounding rock fills the goaf to control and manage the ground pressure. It mainly includes single-layer caving method, layered caving method, segmented caving method and staged caving method.

(1) Single layer caving method. It is mainly used to mine gently inclined ore seams with unstable roof rocks and generally less than 3m thickness. The ore layers between stages are divided into ore blocks, and the mining work of the ore blocks is carried out along the direction according to the full thickness of the ore body. When the mining working face advances to a certain distance, in addition to retaining the space required for mining work, the pillars are recovered in a planned manner and the roof of the goaf is collapsed, and the collapsed roof rock is used to fill the goaf to control the roof pressure. According to the working surface form, it can be divided into long wall caving method, short wall caving method and approach caving method.

(2) Layered caving method. Mining blocks are mined from top to bottom according to layers. After the ore in each layer is mined, the overlying caving rock moves down to fill the mining area. Layered mining is carried out under the protection of artificial roofs, which isolate the ore from the collapsed rock, thereby ensuring that ore loss and dilution are minimized.

(3) There is a bottom column segmented caving method. This method is also called the segmented caving method with bottom structure. The main features are: first, mining is carried out one by one in sections; second, there is a bottom structure dedicated to mining at the bottom of each section, and section mining is carried out section by section from top to bottom. It can also be divided into horizontal deep hole mining and bottom column segmented caving method and vertical deep hole mining and bottom column segmented caving method.

(4) Sectional caving method without bottom column. There is no bottom structure consisting of a dedicated mining tunnel at the lower part of the segment, and the rock drilling, ore collapse, and mining of the segment are all carried out in the mining tunnel.

(5) Stage caving method. The mining height is equal to the total height of the stage, which can be divided into staged forced caving method and staged natural caving method. The staged forced caving method can be divided into the staged forced caving method with compensation space and the staged forced caving method with continuous mining.

3. Fill mining method:

As the mining face progresses, the goaf is gradually filled with filling material. Sometimes brackets are used in conjunction with filling materials to protect the goaf. The purpose of filling the goaf is mainly to use the created filling body to manage ground pressure to control surrounding rock collapse and surface subsidence, and to create safe and convenient conditions for mining. Sometimes it is also used to prevent internal fires in spontaneously igniting ores. According to the ore block structure and the direction of mining working face advancement, it can be divided into single-layer filling mining method, upward layered filling mining method, downward layered filling mining method and split mining and filling mining method. According to the filling materials and output methods used, it can be divided into dry filling mining method, hydraulic filling mining method and cemented filling mining method.

(1) Single-layer filling mining method. It is suitable for gently sloping thin ore bodies. The wall mining face with the entire length of the ore block is used to mine the entire thickness of the ore body along the strike direction. As the working face advances, the goaf is filled with water or cement in a planned manner to control the roof.

(2) Upward horizontal layered filling mining method. Generally, ore blocks are divided into mining rooms and mining pillars. The first step is to return to the mining room, and the second step is to return to the mining pillar. When returning to the mining room, proceed horizontally in layers from bottom to top. As the working surface advances upward, the goaf is filled layer by layer, leaving a working space for continued mining. The filling body protects the surrounding rock on both sides and serves as a working platform for mining. The collapsed ore falls on the surface of the filling body, and the ore is mechanically transported to the chute. When the topmost layer of the mine house frame is mined, top filling is carried out. The ore pillar will be mined after several ore rooms or the entire stage are mined out. The filling method of mine frame mining can be dry filling, hydraulic filling or cement filling.

(3) Upward inclined layered filling mining method. The difference between this method and the upward horizontal layered filling method is that inclined layered mining is used, and the transportation of ore and filling material in the stope mainly relies on gravity. This method can only be used for dry filling.

(4) Downward layered filling mining method. It is used to mine non-ferrous metal or rare metal ore bodies where the ore is very unstable or the ore and surrounding rock are very unstable, and the ore grade is very high or the value is very high. The essence of this mining method is: mining in layers from top to bottom and filling layer by layer. The mining work of each layer is carried out under the protection of the artificial false roof of the previous layer. The mining layering level may be at an inclination angle of 4° to 10° or 10° to 15° with the horizontal. Inclined layering is mainly for direct filling of the roof, and is also beneficial to ore transportation, but rock drilling and support operations are not as convenient as horizontal layering.

(5) Separate mining and filling mining method. When the thickness of the ore vein is less than 0.3~0.4m, only mining workers cannot work in it. The ore and surrounding rock must be recovered separately to make the goaf area reach the minimum thickness allowed for work (0.8~0.9m). The mined ore must be transported The mine is exited from the stope, and the excavated surrounding rock fills the goaf area to create conditions for continued mining. This mining method is called separate mining and filling method.

(6) Square frame filling mining method. In the past, horizontal support pillars or wooden shed support mining methods were often used to mine thin ore veins. This mining method is still a new method when the thickness of the ore body is large, the ore and surrounding rocks are extremely unstable, the shape of the ore body is extremely complex, and the ore is precious. Efficient mining methods.

Selection of metal ore mining methods

The basic requirements for choosing a mining method are: safety, low ore dilution, high ore recovery rate, high production efficiency, high economic benefits, and compliance with relevant laws and regulations. The main factors affecting the selection of mining methods are the geological conditions of the deposit and the technical and economic level of mining.(xingaonai)