Mining is the extraction of economically valuable minerals or other substances from the ground, and all mining sites are mineral-rich deposits. Mining techniques are basically divided into two forms: open pit mining and underground mining. After exploration and feasibility studies are completed, ore is mined from the surface or underground using machinery such as excavators, drills, explosives and trucks.
2. Crushing mining process
The ore mined is very large. At present, the maximum ore particle size of open pit mines is 1000mm1500mm, and the maximum ore particle size of underground mines is 300mm600mm. Due to the close symbiosis of useful minerals and gangue minerals, such large ores cannot be directly separated. To separate them from each other, the ore must be crushed to a certain particle size before the next beneficiation operation.
3. Transportation during mining
Typically, belt conveyors are used to feed bulk ore to primary and secondary crushers, and then feed the crushed ore to vibrating screens to obtain different sizes.
4. Screening of the mining process
The screening process also plays a different role in the gold mining process.
Pre-screening: Before the ore enters a certain stage of the crusher, pre-screening the qualified products that meet the requirements. This process not only prevents the ore from being over-crushed, increases the productivity of the crusher, but also prevents the crusher from clogging.
Inspection and screening: After crushing, screening should be carried out to check the particle size of the crushed products, so that the unqualified extra-large ore particles can be sent back to the crushing operation to be crushed again.
5. Grinding during mining
Crushing is a continuation of the crushing process. Its purpose is to separate most of the useful mineral particles in the ore into monomers and classify them so that the particle size meets the requirements of the classification operation. In general, we support the principle of grinding more and grinding less to save costs.
6. Classification of mining processes
Classification: In the medium, substances are divided into different particle sizes according to different sedimentation rates.
The purpose of classification and screening is to separate the ore particles into different particle sizes, but their working principle and the particle size characteristics of the product are different.
The sieving should be strictly separated according to the sieving size;
Distinguish and classify materials according to the different settling velocities of materials in the medium.
In the grinding process, the qualified materials are usually separated in time by the method of classification, so as to avoid the excessive grinding of the ore and improve the grinding efficiency. Commonly used equipment are spiral classifiers and cyclones.
The gold mining process mainly includes the following methods: cyanidation, flotation, gravity separation and mercury amalgamation.
8. Water treatment during mining
Coarse dewatering is relatively easy. Usually natural drainage is used, that is, natural drainage is drained by the gravity of the water itself. Dewatering of fines typically involves three operations: concentration, filtration and drying. Reclaimed water can be used for some parts of mineral processing operations, or it can be discharged after being treated to standards through a water treatment plant.
9. Dry stacking of tailings
Concentrating hydrocyclone + high-efficiency deep cone thickener + high-efficiency multi-frequency dewatering screen, so that the final concentration can reach more than 85%, so as to achieve dry accumulation. The tailings are then used for paving, construction, etc.
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