In recent years, with the continuous enhancement of the national and local government's infrastructure construction such as highway, railway and housing, the demand for high-quality aggregate and machine-made sand is increasing year by year, and the amount of sand and gravel is 10% per year With the continuous attention to resources and environmental protection issues, some local governments have begun to shut down some small gravel plants in a planned way, creating excellent market conditions for the new large-scale and modern aggregate production line. Sand aggregate is developing in the direction of large scale, high standard and modernization.

1、 Brief introduction of aggregate production line

The aggregate production line can be understood as a reasonable combination of crushing, screening, storage and delivery of finished products. Different products have different combination modes. The whole production process can be divided into three stages from the general layout

The first stage: Primary crushing and soil removal screening. The second stage: All levels of crushing and screening combination to produce finished products. The third stage: Storage and delivery of finished products.

2、 General layout rules under different terrain conditions
1. General layout of general layout According to the characteristics of aggregate production process, select a suitable site, according to the mining elevation, build the primary crushing on the mountain to reduce the transportation distance of raw materials; buffer yard, crushing, screening, finished material pile and other use terrain, combined with the production process, layout in stages and sections, which can not only reduce earthwork, but also shorten the belt transportation distance. In front of the plant, there are canteen, bathroom, warehouse, etc. The area in front of the plant and the production area are set in different areas, which can effectively reduce the impact of noise and dust produced by production. The gate shall be arranged near the road outside the plant. According to the material transportation volume, truck scale is arranged on the road entering the production area to measure the finished aggregate.

2. General layout rules under different terrain conditions

Terrain, general layout of its description is usually said to be "More undulating" and "relatively flat" There are two types. In fact, the layout of aggregate production line is more suitable for "large topographic relief". The reason is due to the particularity of aggregate production process: the workshops are connected by belts, the upper workshop discharges materials, the lower workshop feeds materials, the underground (ground) and high-altitude. Reasonable height difference of the platform section can shorten the transportation distance, but there are two workshops with returned materials, and the elevation of the workshop should be the same as possible. It is a test for designers how to make the most reasonable general layout combined with terrain. In view of the small area of aggregate production line, but the complexity of internal connection, combined with the actual design, the following points are explored and summarized. (1) According to the general layout of the first crushing plant, the elevation difference between the feeding hopper and the discharging belt is the same according to the production scale. The elevation difference of 500t / h is about 12M, and that of 1000t / h is about 14m. The cost of trench construction is high. In order to avoid the occurrence of trench or large trench, a place with platform section difference is usually selected to place a broken one, and ensure that there is a large enough unloading platform, generally 50m * 50m. Different sizes of ore transport vehicles are also different. (2) Between crushing and screening at all levels, due to the return of materials between local workshops, it is appropriate to arrange the workshop in one bench section. According to the conveying angle and the vertical elevation of the workshop, the economic and reasonable conveying length between workshops is calculated.

3、 Example of general layout
The project is located in Tangshan city. The general layout principles of the project are as follows:

• The technological process is smooth, short and reasonable;
• In line with the national fire protection, environmental protection, safety, health and other aspects of the specification.

According to the above principles, combined with the process flow, site conditions and external transportation conditions, the general layout is carried out. The scheme is as follows: (1) Aggregate production line layout According to the characteristics of aggregate production process, a flat site is selected as the unloading platform, and the natural elevation difference of the terrain is used to build the primary crushing under the platform section to reduce the civil engineering quantity; according to the process requirements, a relatively open and flat place is selected as the buffer material pile between the first and second crushing; the second crushing, third crushing, screening and finished product stacking are built at a relatively flat position at the foot of the mountain, The finished material pile is close to the gate of the plant, which is convenient for transportation. Office building, canteen, bathroom and other office and living facilities are planned to be built in the front area of the plant. Due to the limitation of site conditions, this area is temporarily planned in the north of land acquisition, which is not included in the design.

(2) Transportation Engineering

Aggregate transportation will be an important part of aggregate management. As the aggregate production line is built on the mountain, the construction of aggregate transportation road is the key. The roads outside the plant need to be built about 800m to the connected trunk road. In order to meet the needs of aggregate transportation, two pairs of 150t truck scale are used to measure the finished aggregate.

(3) Vertical layout

The main production area is divided into three sections from north to South: 845.500 platform section of unloading platform, 832.500 platform section from the first crushing plant to the buffer yard, and 820.00 platform section from the second crushing plant to the finished material pile, and the third stage screening B is located at 830.00 platform section. Good use of the natural terrain.

In the design of aggregate production line, the reasonable general layout should be combined with the terrain to meet the needs of users and ensure the production needs.