An Overview of Possibilities of Increasing the Permissible Speed of Underground Suspended Monorails for Transporting People in the Conditions of Polish Underground Mining

Abstract

The permissible speed of suspended monorails in underground mines is determined by the internal regulations of each country and depends on the type of transportation. In the case of passenger transportation, the maximal driving speed in Polish underground mining regulations is 2 ms−1. Regarding the higher permitted driving speed in other countries, it is reasonable to consider changes to these regulations that would raise the permitted speed limit. Increasing the permissible travel speed would improve the efficiency of mining operations because of the significant reduction in the inefficient working time of miners traveling on the monorail from the shaft to their place of work. However, at the same time, an increase in the permissible speed of travel results in higher values of forces and accelerations affecting both the crew riding the train and the underground working infrastructure (the suspended route, slings, and arches yielding support). The results of the series of works carried out at the KOMAG Institute of Mining Technology to assess the impact of increasing the speed on the safety of both the crew and the mine infrastructure are presented in this article. For this purpose, several numerical simulations were conducted, considering the emergency braking of the suspended monorail during which the overloads are the greatest. The result of the simulations was the analysis of the effects of driving and emergency braking of the suspended monorail with increased travel speed on the following: the overloads acting on the crew being transported and the forces acting on the suspended monorail route, including the forces in each sling. Next, a potential solution for improving safety was developed. The development of the algorithm for an innovative method of sequential emergency braking of the monorail in the case of passenger transportation was one of the important solutions.