The head of the company’s project department Pavel Aleksandrov made a presentation at the conference “Construction technologies, equipment and materials for the mining industry”.
The expert told about the possibilities of using anchor-mesh structures for engineering protection in the mining industry.
There are five typical situations in an open ore pit:
- Areas in which regular rock falls of relatively small rock debris Their fall threatens equipment or personnel.
- Areas of decompactions, cracks, the development of deformations in which creates a danger.
- Areas in which regular rockfalls of low-energy small and large fragments occur.
- Areas of intense destruction of ledge walls.
- Areas offallingdebriswithhighkineticenergy
In the first case, it is advisable to install an anti-rockfall curtain. The essence of the method consists in draping hazardous areas with continuous meshes, which prevent the free fall of debris, reducing the speed of their movement. A trench can be arranged at the bottom of the curtain to collect debris.
In a number of cases, the best technical solution to stop the development of landslides or collapses in the areas, where the serpentine of technological roads is located or infrastructure facilities are located, may be a dowel fastening.
In areas where there are risks of falling debris (with relatively little energy) on transport routes and infrastructure facilities, trapping horizontal barriers are used. Sometimes they are also called “galleries”. Another option is a combination of a barrier and a light curtain. The barrier captures debris falling from the overhead ledges, and the curtain eliminates risks of rockfall below the barrier.
A dam is one of the traditional methods of protection. As a rule, such a structure is located in the immediate vicinity of the protected objects. The dam can be made both as a tight sheeting along the hazardous area, and as a local solution around the protected objects.
As a rule, dams are made in the form of soil shafts, which can be supplemented with barriers. In addition, in the area of falling debris, it is possible to make a damping pad, which reduces the possibility of an elastic impact, preventing rebounds and ricochet of debris.
To protect against debris falling with high energy up to 5 000 kJ (comparable energy is possessed by a Volga car moving at a speed of 200 km /h), it is advisable to install trapping barriers.
Stone trapping barriers consist of retaining and damping elements, as well as a mesh working part. This flexible solution is applicable to various situations:
- protection of the territories of ore pits
- protection of entrance portals of mine excavations
- protection of tailing dump dams and other
Mesh structures can also be used to protect the infrastructure of enterprises and settlements located in mountainous areas from the associated risks – avalanches and mudflows. Snow-retaining shields and mudflow barriers are used for this.
For the structures described above, depending on the tasks to be solved, various types of meshes are used. Diamond netting in high-strength design (up to 150 kN /m) are used, as a rule, as curtains, a covering system of dowel fields or as a second layer in the structures of anti-rockfall barriers, fences, snow-retaining shields. They can also be strengthened with steel ropes. The so-called chain mail nettings are characterized by higher values of strength, but also by a large intrinsic deformability.
Various types of ground anchors are used as anchorage. First of all, it should be noted the multifunctional geotechnical system (MGTS) GEOIZOL-MP, which is produced by the «Pushkin Machine-Building Plant» (part of the GEOIZOL Group of Companies). Bored injection anchors are used to create a strong and reliable fastening of engineering protection structures in all types of soil and climatic conditions. Their installation is possible in hard-to-reach places using climbing equipment.
The conference “Construction technologies, equipment and materials for the mining industry”, organized by the International Association of Foundation Contractors, took place on April 21, 2021 in Moscow at the Crocus Expo IEC, as part of the 25th international exhibition of machinery and equipment for mining, processing and transportation of minerals MiningWorld Russia.