There are many options available for ensuring the stability of mines and rockbolts are a popular option. Most of the time when shotcreting is used, rockbolting will be as well. There have been many advancements in rockbolting technology and increasingly complex rockbolts are being used. There are still situations where simple technology is used as well but there is a variety of options available now that can ensure the safety of the mine.
There are many companies that provide rockbolt testing such as Mine Civil IT. These allow you to get an idea of the performance of the rockbolt. Rockbolting is most commonly seen in coal mines but you can see it in metal mines as well, but to the same extent. There are different types of rockbolts that are used for stabilising mines and these are friction, grouted and mechanical rockbolts. These come with their own pros and cons therefore, you need to assess the situation before determining which type is needed. Mechanical rockbolting is the traditional method and this is also the simplest. Because it has been around a long time, it has been used in a variety of situations. They were traditionally used with slot and wedge bolts. But these have now been replaced by expansion shells.
Passive ground support was most used and therefore mechanical rockbolts actually provided a quick solution. Here, a hole will be drilled at a specific site and then the bolt will be inserted with the surface plate. It will be kept in place by tightening the nut. But for further strength and to protect the bolt from corroding, cement grouting can be done. But there is a big advantage in grouting only on point which is what led to the use of grouted rockbolts where the bolt will be fully encased in grout inside the hole. This takes a little bit more time than the mechanical bolt as the cement needed time to cure. But now, resin has replaced the use of cement as it cures faster and comes with easy handling. However, use of resin is more expensive compared to cement.
In a friction bolt
You need to have contact with the rock along the full length of the bolt. This is what provides the support. These are very easy to install. There are Swellex and split set friction rockbolts that can be used. High pressure water is used in the installation of Swellex while a drill will be used to place the split set tube into position. You need to consider the local parameters to decide which rockbolting system is best suited for your property. Some of these parameters include the location where the bolt is to be placed, presence of lamination, competence of the rock mass at site and the duration for which you require active support. The budget for active support will also be considered alongside feasibility. If you are looking for a short term solution, then an expensive system designed for long term should not be considered.