For the underground mining of the Lenhardt-Petrasch marble deposit two sublevel stoping methods are developed and compared with a Raise mining method, planned already in a previous study. The tabular deposit of white marble dips with around 60° to the south and has an average thickness of around 30 m. The hanging wall consists of competent layers of rock. A comparison of possible mining methods showed that sublevel stoping with downwards fan drilling, sublevel stoping with parrallel vertical downwards holes and Raise mining are the three most promising mining methods. For these three methods the primary and secondary development and the mining sequence is planned and a calculation of capital and operating costs is done. For raise mining only one access adit needs to be developed while for the sublevel methods four adits are required. With raise mining every stope is undercut on the haulage level and a raise is developed in the centre of the stope to the upper end of the deposit. From this raise, extraction is done by drilling and blasting with nearly horizontal blast hole fans. For the two sublevel stoping methods in a first step from a crosscut a slot is developed along the hanging wall and in a second step drilling is started downwards either with fans or with parallel blast holes. The cost calculation shows lower costs for Raise mining especially in the narrow parts of the deposit. In addition Raise Mining is more flexible to follow the varying geometry of the deposit.
|Translated title of the contribution||Development of a sublevel stoping method for the Lenhardt-Petrasch marble deposit|
|Award date||30 Mar 2007|
|Publication status||Published - 2007|
Bibliographical noteembargoed until null
- Underground Mining Raise Mining sublevel stoping marble mining methods