A tailings pond is a place composed of dams to intercept valley mouths or enclosures and is used to store metal or non-metal mines for ore sorting and discharge tailings or other industrial waste. A system of structures constructed for tailings disposal is called a tailings facility. In this article, we will introduce the composition, types, characteristics, and location principles of tailings ponds.
Composition of Tailings Pond
A tailings pond is generally composed of a tailings storage system, a tailings pond flood discharge system, and a tailings pond backwater system.
1. Tailings storage system
The system generally includes an ore drawing pipeline on the dam, initial tailings dam, late tailings dam, infiltration line observation, displacement observation, and seepage drainage facilities.
2. Tailings pond flood discharge system
The system generally includes structures such as intercepting trenches, spillways, drainage wells, drainage pipes, and drainage tunnels.
3. Tailings return water system
Most of the systems use the flood discharge wells and pipes in the reservoir to introduce the clarified water into the downstream return pump station, and then raise it to the high-level pool. There are also active pumping stations set up on the edge of the water surface in the reservoir to directly extract clarified water and raise it to a high-level pool.
Characteristics of Tailings Pond
1. The tailings pond is an indispensable facility for the production of the mine concentrator
The tailings pond is the largest environmental protection project for mining enterprises. It can prevent the arbitrary discharge of tailings to rivers, rivers, lakes, seas deserts, and grasslands. As long as tailings are produced in the ore dressing plant of a mine, a tailings pond must be built. Therefore, the tailings pond is an indispensable part of the production of the mine concentrator.
2. High cost of tailings pond construction
The capital construction investment of tailings pond generally accounts for more than 10% of the total investment in mine construction, accounting for about 20% of the investment in the concentrator, and some almost approach or even exceed the investment in the concentrator. The operating cost of tailings facilities is also high, and the operating cost of tailings facilities in some mines accounts for more than 30% of the production cost of the concentrator. In order to reduce operating costs, the location of the concentrator in some mines depends on the location of the tailings pond.
3. The tailings pond is the biggest source of danger for the production of mining enterprises
Tailings ponds are a hazard for man-made debris flows with high potential. Over a period of more than ten years or even decades, various natural (rain, earthquake, rat holes, etc.) and man-made (mismanagement, uncoordinated relations between workers and peasants, etc.) unfavorable factors are constantly or periodically threatened its safety. Facts have repeatedly shown that once the tailings pond collapses, it will cause huge disasters and losses to industrial and agricultural production and downstream people’s lives and properties.
Types of Tailings Ponds
1. Valley-type tailings pond
A valley-type tailings pond is a tailings pond formed by building a dam at the mouth of a valley. Its characteristics are that the initial dam is relatively short, the dam body engineering volume is small, and the tailings dam is relatively easy to manage and maintain in the later stage. When the dam is high, a larger storage capacity can be obtained; The water clarification distance and the length of the dry beach can easily meet the design requirements; however, when the catchment area is large, the amount of flood discharge facilities is relatively large. Most of the existing large and medium tailings ponds in my country belong to this type.
2. Mountainside Tailings Pond
The mountain-side tailings pond is a tailings pond surrounded by a dam at the foot of the hillside. Its characteristics are that the initial dam is relatively long, and the engineering volume of the initial dam and the later tailings dam is relatively large; due to the short depth of the reservoir area, the clarification distance of tailings water, and the length of the dry beach are limited, and the height of the later dam is generally not too high. high, so the storage capacity is small; although the catchment area is small, the flood regulation capacity is low, and the influent structures of the flood discharge facilities are large; due to the poor clarification conditions of tailings water and flood control conditions, management and maintenance are relatively complicated. . This type of tailings pond is often used in small and medium-sized mines in the low mountain and hilly areas in China.
3. Flat-type tailings pond
The flat-type tailings pond is a tailings pond surrounded by dams around the flat terrain. Its characteristics are that the initial dam and the later tailings dam construction volume is large, and the maintenance and management are more troublesome; due to the surrounding dams, the area of the reservoir area is getting smaller and smaller, and the slope of the tailings sedimentary beach is getting slower and slower, so the clarification distance and dry beach length are And the flood control capacity is reduced accordingly, the height of the dam is limited and generally not high, but the catchment area is small, and the drainage structures are relatively small; such tailings ponds are often used in the domestic plains or desert Gobi areas.
4. Cut river tailings pond
The intercepting river type tailings pond is a tailings pond formed by intercepting a section of the river bed and damming the upper and lower ends of the riverbed respectively. Some leave a certain flow width on the wide and shallow riverbed and build dams on three sides to form a tailings pond, which also belongs to this category. Its characteristics are that it does not occupy farmland; the catchment area of the reservoir area is not too large, but the catchment area upstream of the tailings pond is usually large, and a drainage system must be set up in the pond and upstream of the pond, which is complicated in configuration and large in scale. This type of tailings pond maintenance and management is relatively complicated, and it is not widely used in China.
8 Principles for Site Selection of Tailings Ponds
The correct selection of tailings pond site is extremely important. In the design, it is generally necessary to select multiple warehouse locations and make a technical and economic comparison to determine it. The following principles should be considered comprehensively when looking for a warehouse location
- The storage capacity of a tailings pond strives to accommodate the tailings of the entire production life. If there are indeed difficulties, the service period should not be less than five years.
- The storage site should be close to the concentrator, preferably in the downstream direction of the concentrator. The tailings conveying distance can be shortened, the lift is small, and the adverse effects on the dressing plant can be reduced.
- Try to be located in the downstream direction of large residential areas, water sources, aquatic bases, and key protected historical sites.
- Try not to occupy or occupy as little farmland as possible, and do not move or move villages less often.
- Without technical demonstration, it should not be located in the upper part of the mineral deposit with mining value.
- The catchment area of the reservoir area should be small, the depth should be long and the vertical slope should be gentle. The size of the flood drainage system can be reduced.
- The mouth of the reservoir area should be small, and the “belly” should be large. It can make the initial dam project small and the storage capacity large.
- Try to avoid being located in areas with adverse geological phenomena to reduce processing costs.