Open-cut mining process is a method of mining useful minerals directly from the surface. Mine tunnels created by open-pit mining are generally called open-pit mines.
1. Classification of the enclosed ring and open pit mine
Closed circle: the plane closed curve of the surface of the open pit.
Depending on the buried topographic features of the deposit and the surface closed circle of the open-pit mine boundary, it can be classified as either hillside open-pit mining or depression open-pit mining.
- Hillside open pit – above the surface closed circle;
- Sunken open pit – below the surface closed circle.
2. Three elements of open-pit mine
Bench: divide the ore and rock into horizontal layers with a certain thickness; during mining, each layer forms a ladder pattern in space. Each step is called a step, and its height becomes the step height.
Bench slope: the inclined surface of the bench facing the goaf. The angle between the inclined plane and the horizontal plane is called the step slope angle.
Step platform (flat plate): the horizontal space between the slope bottom line and slope top line. Platform width is the distance between the slope bottom line and slope top line, and the platform used for blasting, shovel loading, and transportation is called a working platform; working platform height is the distance between the edge of the blasting pile and slope top line; the platform used to intercept sliding rocks is called a safety (cleaning) platform.
3. Mining technology of open-cut mining process
The mining process of open-pit mine is relatively simple, mainly including perforation, blasting, mining, loading and transportation and rock drainage.
The open-cut mining process includes manual mining, mechanical mining, hydraulic mining and dredger mining.
(1) Manual mining mainly relies on manpower to drill holes, load ore, and cart.
(2) Hydraulic mining is to uses a water gun to shoot high-pressure water to flush mining stones and use hydraulic flushing to transport them. This method is mostly used to mine soft sand deposits.
(3) Mechanical mining involves using certain mining and transportation equipment to engage in mining operations within open spaces, and transport ores and rocks out of the mines through open-pit ditches or underground passageways.