Mining activity produces metal sulfide wastes particularly pyrite which remain in the mine long after operations cease. When water percolates through a mine where oxygen is present, a series of chemical reactions occur which produce extremely low pH and high concentrations of toxic sulfate and metal ions. This toxic leachate can cause severe aquatic habitat degradation downstream of the mine. T...

Mine earthquakes are serious disasters in coal mines, especially extremely thick hard strata. This study investigates the occurrence mechanism of fracture-type mine Hydraulic fracturing by ground vertical well was used for shock absorption. Dongtan taken as a case study. Field investigation, theoretical analysis, industrial tests, and field monitoring were revealing mechanism. First, mechanical...

The paper describes a distributed temperature sensing system that was used to monitor the artificial freezing of soils during construction potash mine shaft. technique reconstructing field by solving inverse problem in entire volume frozen using measured temperatures four thermal monitoring (TM) wells is described. Two local anomalies distributions TM are described and analyzed theoretically th...

This paper describes the results of temperature monitoring a frozen wall (FW) around skip shaft potash mine under construction. The data on measurements in control-thermal boreholes were used to parameterize mathematical model heat transfer, which allowed for reconstruction field throughout entire cooled and soil volume. resulting distribution FW zone greater than 1 year was determine strength ...

Turbo generator shafts are often subjected to cyclic torsion resulting in formation of large longitudinal cracks as well as circumferential cracks. The presence of these cracks could greatly impact the shaft resonance frequencies. In this paper, dynamic response of a shaft with longitudinal and circumferential cracks is investigated through a comprehensive analytical study. The longitudinally c...

in this paper, the effects of transverse cracks on rotating shaft were studied. according to earlier works, crack shaft failure decrease the critical speed of the shaft and also exhibit a nonlinear vibration behaviour leading to increases the amplitude of 1x and 2x harmonics (first and second order of rotational speed in torsional vibration). this suggests that the application of order analysis...

The article addresses the problem of functional purpose shaft-type furnaces with chimneys found at Late Bronze Age sites Northern Eurasia. This category thermal engineering structures became widespread in eastern wing West Asian (Eurasian) metallurgical province. Thermal sets flue channels are physical evidence implementation technological algorithms pastoral model metal production based primar...

Abstract. The new mineral species freitalite, C14H10, corresponding to the aromatic hydrocarbon anthracene, has been discovered on mine dump of Königin Carola shaft (also named Paul Berndt Mine), Freital, near Dresden, Saxony, Germany. forms thin blades or flakes irregular shape up a few millimetres in size and shows an intense violet whitish-violet white colour. Freitalite is product pyrolysis...

Robots promise to enhance minimally-invasive surgery, but flexion of the thin instrument shaft introduces error into models of the robot kinematics. Visual or electromagnetic tracking of the instrument tip provides correct forward kinematics, but uncertainty in shaft bending and port location leaves residual errors in inverse kinematics. These errors can cause incorrect motions that preclude th...