Securing a gateway behind the longwall frontage is a problem that underground mines have faced for decades despite numerous attempts to improve this process. Due to an innovative approach, the patent no. P413645 obtained by FAMUR SA in December 2018 will undoubtedly facilitate work for miners and have a beneficial impact on the efficiency of the entire longwall system.
Many hard coal mines are forced to keep one or two gateways behind the longwall face (frontage). This is not an easy task. At first, cribs and wooden stacks filled with stones were used, followed by the so-called big bags with binding material. Still, the modernised versions of such methods were time-consuming, which had a negative effect on the efficiency of the entire longwall system.
The new patent by FAMUR takes advantage of the opportunities that the present state of the art provides and it constitutes a creative compilation of many existing solutions. The general idea consists in suspending a big bag to a slightly-modified powered roof support, through which the bag maintains its shape when being filled with quick-setting binding material. This process already begins under the powered roof support and does not require any additional support structure (guarding) to be applied. When the filling material begins to harden, it ‘memorizes’ the shape and advancing the powered roof support makes it possible for an even partially-filled bag to stand without supporting. Then all you need to do is to fill up the bag with the binding material.
The proposed method is much less time-consuming and labour-absorbing compared to the previous methods. Moreover, having made small changes, this process may also be used with every type of powered roof support manufactured by FAMUR SA: caving, backfilling, or top coal caving one.
Read more in the article ‘Solving the unsolvable. FAMUR has patented a new method of securing gateways behind the longwall face’.