Published time：15 August 2024

Tunnel waste rock is a by-product generated during the construction of tunneling or underground projects. It usually includes materials from rock or soil layers when digging tunnels, underground passages, mines, or other underground structures. These materials are generally a mixture of rocks, soils, or other geological materials and are no longer suitable as materials for engineering construction.

The main characteristics of tunnel waste rock include:

Source diversity: Depending on the geological conditions of the construction site, tunnel waste can be various types of rocks (such as granite, limestone, shale, etc.) or soil.

Large volume: Due to the large scale of tunnel projects, the volume of tunnel waste excavated is also quite large.

Environmental treatment: Due to its large volume and lack of direct utilization value, how to treat and dispose of these waste rocks poses a challenge to ecological management. Usually, tunnel waste may be used for backfilling, embankment construction, or road construction.

Potential secondary use: In some cases, these waste rocks can be reused in engineering construction after treatment, such as preparing concrete aggregates, roadbed materials, etc.

Tunnel Waste Rock Sand Making

Tunnel Waste Rock Sand Making

Tunnel Waste Rock Processing Sand and Gravel Aggregate

Tunnel slag and waste rock is a common industrial waste, which refers to the waste stones and stone chips generated in the mining process of caves and mines. These tunnel slag and waste rocks usually contain certain mineral components and strength. After proper treatment and processing, they can be made into sand and gravel aggregate suitable for construction.

Advantages of tunnel slag and waste rock into sand and gravel aggregate

Waste rock is often discarded or piled up, occupying a large amount of land resources, and also causing certain pollution to the environment. However, by using tunnel slag and waste rock to prepare sand and gravel aggregate, tunnel slag and waste rock can be fully utilized, waste emissions can be reduced, environmental pollution can be reduced, resource recycling can be achieved, production costs can be reduced, sustainable development can be achieved, and a virtuous cycle of the economy can be promoted.

Tunnel slag is the stone in tunnel mining. It has a hard texture. It is processed into crushed stone by machinery and equipment. It is not only of good quality but also has uniform particles. It can be used as concrete construction aggregate in actual production. As long as the conditions are met, the tunnel can be made of sand. The slag is mostly sandstone and granite. The main indicators of the produced machine-made sand are controlled at fineness modulus 3.0±0.2, stone powder content 7-10%, methylene blue value 1.0-1.2, machine-made sand crushing value 12%-16%, and other indicators meet the requirements of fine aggregate in TB10424-2018.

Crushing Process of Tunnel Slag And Waste Rock

The slag and waste rock are processed into sand and gravel aggregate. According to different processing conditions, 2-4 crushing processes can be adopted.

Second stage crushing: jaw crusher + impact crusher, or jaw crusher + cone crusher. Second-stage crushing can produce 5-10mm, 10-15mm, 15-20mm, and 20-31.5mm building crushed stone.

Three-stage crushing: jaw crusher + impact crusher + sand-making machine, or jaw crusher + cone crusher + sand-making machine, with the addition of sand making, it can produce crushed stone of different specifications, and can also produce 0-5mm machine-made sand.

From the configuration, it can be seen that the difference between two-stage crushing and three-stage crushing lies in the second crushing. If the slag raw material is of medium and low hardness, the second crushing can be impact crushed; if the raw material is of medium and high hardness, the second crushing can be cone crushed.

Four-stage crushing: jaw crusher + single-cylinder cone crusher + multi-cylinder cone crusher + sand-making machine, or other combination configurations.

Screening: The crushed materials are classified by particle size through screening equipment and washed as needed to remove impurities and improve material quality.

What kind of crusher is used to process tunnel waste?

According to the industry situation, it is recommended to choose fixed (jaw crusher, impact crusher) and mobile crusher, with an hourly output of 10-2000 tons and a full range of models. Reasonable selection can be made according to the actual site conditions, output, and finished material requirements.

1. Fixed tunnel crusher

It needs to be recovered from the demolition site and transported to the processing site for processing. Pile driving is required during construction. It is suitable for stable sites, large scale, relatively fixed raw materials, and low initial investment costs.

Jaw crusher: Suitable for large-size waste slag, adopts the extrusion crushing working principle, its crushing cavity is deep (V-shaped), and there is no dead zone, which increases the throughput, uses oversized bearings and forged spindles, and bears greater crushing force. In addition, the flywheel design and hydraulic design effectively reduce vibration and run more smoothly, the discharge port gasket is adjusted and the finished product specifications are complete.

Impact crusher: Generally, tunnel waste slag is crushed at the second level or above, and an impact crusher is used to increase the crushing shape. The new concept crushing technology can meet the crushing of different material specifications and fully meet the new process requirements of “more crushing and less grinding”. The gap between the impact plate and the hammer can be easily adjusted to effectively control the particle size of the material. At the same time, a large number of new high-wear-resistant materials are used to reduce the wear of worn parts and save costs.

impact crusher jaw crusher machine portable jaw crusher

2. Mobile tunnel crusher

One machine can build a factory and directly arrive at the demolition site for recycling. Through the on-board system, it is convenient for road transportation and site penetration, saving the cost of raw material operation and ground piling. It is suitable for processing plants with complex sites and unfixed raw materials, and the operating investment cost is low.

The machine model has a centralized design, simplified process flow, and an on-board electronic control system, all lines have been connected and debugged before leaving the factory, and only an external power supply is required to produce when arriving at the site. The automatic control system realizes one-button adjustment and is equipped with a maintenance platform to facilitate understanding of production conditions.

The choice of crushing equipment should be determined according to the hardness, composition, and final use of the waste rock to ensure efficiency and product quality.

Crushing of slag and waste rock is an important technical means of resource utilization. Through scientific processing procedures, waste can be effectively converted into useful building materials, achieving a win-win situation in economic and environmental benefits.