For the control of the stability of the underground mining works there are very used techniques such as the use of split rock bolts, swellex, cable, among others. However, there are other support techniques that are used in underground mining, which are mentioned below.
Reinforcement of pillars
In important pillars associated with permanent excavations, when these are unstable, it is usually used: through bolts, through cables or cables wound to the pillar, the latter known as the piling of columns, in such a way that the unstable pillar is stabilized.
The cables used are the same reinforcement cables for the support of mining excavations.
Uses of reinforced concrete
Reinforced concrete structures can be used to make concrete coverings of important permanent excavations such as pit stations, level galleries, main mineral deposits, etc. or associated to the work of preparation of methods of mining by subsidence. Also the reinforced concrete is used to build concrete walls in the gables of mining works, alone or as a complement to the support with forms. On the other hand, they can also be used to build slabs at the base of the cuttings, in such a way that they serve in the future as roof of the tenements that will be located below to recover the mineral. These structures must be rigorously designed and constructed, comparable to civil engineering works. Rock mechanics provides the necessary tools to do these jobs.
The techniques of consolidation of very poor quality land by injections of cement slurry or chemical products, are rarely used in underground mining, however, in some cases it may be necessary, particularly associated with the construction of important permanent excavations.
Corrugated iron piles
In relation to the support with forms, an alternative of the marchavantes is the use of cement piles cemented or not cemented, placed as a pre-support, to improve the quality of the roof, especially if the roof is raised or is very unstable.
They are corrugated iron structures used as a light formwork in the advance work, in poor quality rock conditions, generally in combination with the shotcrete.
Linked with cables and blasting of relaxation
In advance work located in environments of very high stress, prone to occurrence of bursting or bursts of rocks, the adequate support is based on cemented bolts or with resin and mesh. To minimize the effects of bursting or bursts of rock, in addition to the bolts and mesh is usually used linked cables.
Likewise, in high stress environments, the relaxation blasting technique is an alternative to stability control.
This consists of drilling and loading long drills in the front of advance next to the production drills. Simultaneous blasting of long drills and production drills, propitiates the fracturing of the rock beyond the limits of production blasting. The fracturing of the rock contributes to relax the efforts, canceling the possibility of occurrence of reventazones