Shaft reaming machine for maintenance of mine shafts in the salt rock mass

Due to rheological properties of salt rock mass, maintenance of mine excavations, including shafts may be very challenging, especially in the long term. Many different ideas and approaches to a subject of sinking and maintaining a shaft in salt rock mass have emerged over the years, of which the main directions include two opposite ideas, such as an application of high-strength lining and an approach based on flexible lining. The article presents a shaft reaming machine designed for maintenance of mine shafts located in salt rock mass designed with a flexible shaft lining approach

The effect of geochemical processes on groundwater in the Velenje coal basin, Slovenia: insights from mineralogy, trace elements and isotopes signatures

This study investigated the mineralogical and isotopic composition of groundwater and precipitation to identify and constrain geochemical processes within stacked Pliocene and Triassic aquifers in the Velenje coal basin. Scanning electron microscopy combined with energy-dispersive X-ray spectroscopic analysis revealed that suspended matter in the Pliocene aquifer consists of feldspars and quartz, while dolomite, calcite and feldspars are present in the aquifer dewatering Triassic strata. The concentrations of trace elements in Triassic and Pliocene aquifers range from highest to lowest Zn > Fe > Ni > Al > Ba > Mn > B > Li > Mo > As with the majority of trace element concentrations below international drinking water health guidelines. Multivariate principal component analysis indicated that concentrations of Mn, Ba, Eu, Cs, Y, Li and T, pH, conductivity and dissolved oxygen in samples were the best chemical parameter for distinguishing the two aquifers. A significant positive correlation (p < 0.05) was found between Ni, Mn, Co, Zn, As and Mo. Groundwater in the Pliocene aquifer likely has an external source of carbon based on the delta C-13(CO2) values (- 12.3 to - 3.6%). The groundwater also has detectable levels of dissolved methane with isotopic values (-77.7 to - 51.4 parts per thousand delta C-13(CH4); -247 to -162 parts per thousand delta H-2(CH4)) consistent with microbial methanogenesis. The groundwater in the Triassic aquifer has tritium values (up to 4.1 TU H-3) characteristic of modern recharge (< 50 years), while the lack of detectable H-3 (0TU) in the Pliocene aquifer is consistent with longer residence times.6 month embargo; published online: 31 October 2019This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]