Separate deposition of metals from highly concentrated solutions with granulated magnesia-silicate reagent

Multi-stage deposition of metals from a sulfate solution with a high concentration of iron, aluminum, copper, zinc, and nickel has been studied. The concentrations of the components correspond to the composition of the sub-basement waters of the Gaisky GOK. Granular magnesia-silicate reagent based on serpentinite (Khalilovsk magnesite deposit, the Orenburg region, Russia) has been used as an alkaline agent. The magnesia-silicate reagent's ability to reduce the acidity of solutions is due to the presence of products of destruction of the original serpentine mineral, mainly magnesium oxide. The results of the solutions multi-stage purification from metals simulation have been presented. It has been found that the reagent did not wholly exhaust its activity during a single contact with the solution. Therefore, the possibility of its repeated use for the 2nd and 3rd time has been studied. As the solution is neutralized according to the known pH range of the beginning and complete deposition of metal compounds, first iron, and then aluminum are deposited. For copper and nickel, the effect of co-precipitation is observed until the pH of precipitation of poorly soluble compounds is reached. Iron is the main component of precipitations at the 1st, 2nd, and 3rd stages, which corresponds to pH = 2.4-3.7. At the 4th stage (pH = 4.0), the precipitations consisted mainly of aluminum compounds. The copper and nickel content in precipitations increase due to decreased concentration of major components (aluminum and iron) and a pH increase. The deposition of zinc from the solution occurs not to the precipitations, but on the granules surfaces. Precipitations enriched in aluminum and iron have been obtained. Sorption and co-precipitation processes have been observed for copper, zinc, and nickel, which prevents individual precipitation by these metals. Thermally activated serpentine minerals can be considered a promising alkaline reagent for technogenic solutions neutralization and purification.

Evaluation of geomechanical conditions at Magnezitovaya mine when undermining natural and anthropogenic objects

Development of Satka magnesite deposit is carried out in complicated geomechanical conditions, in particular, mining works are conducted under the Bolshaya Satka river, in the zone of influence of the existing and developed quarries. Underground workings undermine a number of surface objects of industrial and civil purpose: railways, bridges, buildings and structures. There was an urgent need to conduct special studies of geomechanical conditions at the mine in order to assess the feasibility of working off part of the safety pillars located under the railway tracks of "Russian Railways", PJSC and the river bed. In the process of research, the main physical and mechanical properties of rocks have been identified, and the initial natural stresses of the rock mass have been measured. An increased level of horizontal initial stresses in the zone of safety pillars at the horizons + 180. + 260 m was detected. Based on the results of the research, a conclusion was made on the need to develop some engineering measures to ensure the safety of underground works. It was recommended, to ensure the stability of the rocks massif, to apply the option of extracting the treatment chambers with the formation of the ceiling of the vaulted form. It is proposed to monitor deformation processes in mine workings and on the daylight surface. To this end, the installation of an automated control system for rock pressure is recommended. It is necessary to provide for the establishment of long-term observation stations for controlling rock pressure and displacement. According to the results of the research, "Guidelines for the safe control of mining operations at bump-hazardous Satka magnesite deposit" have been developed in accordance with the requirements of the Federal norms and regulations in industrial safety.