Based on the research results carried out earlier and updated by the new data reflecting the modern condition of mining operations at the PC “Belaruskali” mines of the Starobin deposit , shown the changes of deformation and reological properties of clay and salt rocks and forms of underground pressure appearance at the mining depths of 800 m and more.
Approaches to selection of technological mining schemes based on selective potash seam extraction are described. Progressive technological mining schemes for potash mining company «Belaruskaliy» and the geological conditions of the IV potash horizon are reviewed. Basic aspects of the geomechanical substantiation of parameters of technological mining schemes for conditions of the new potash horizon in the presence of influence of the overlying horizons are also presented. Guidelines for substantiation of progressive mining methods for the conditions of the IV potash horizon (Third Mine, «Belaruskaliy») are developed on the basis of the modeling of the stress-and-strain state of the rocks.
The article is devoted to research of probability of sudden salt rocks outbursts on the basis of measuring of their volume shrinkage. The design scheme of the device for measuring quantity of the microincluded gases in rocks is proposed. Criteria to estimate the possibility of sudden salt rocks outbursts is revealed.
Technological scheme of selective extraction of a complex thick potash seam on the basis of cutting machine «Bucyrus Model 25 M0» is proposed. Stable pillars’ width and room dimensions are calculated. Economical effect is also presented.
The paper presents results of feasibility study into recovering non-commercial reserves of mined horizons at the Starobinskoe potassium deposit. Topicality of this task is explained by a rather intensive reserve depreciation at the RUP PO Belaruskaliy Company and the fact that developing new horizons is a capital-intensive task which requires additional geological prospecting activities.
The paper studies formation processes of geological dislocation of the syncline type at the Staroobinsk potassium salt deposit. A fundamental difference in formation of outburst and outburst-safe synclines has been established with application of advanced 3D modeling software.
The paper provides information on the distinctive features of the geological structure of the Starobinsky deposit's formations and the current mining methods used at Levels II and III. Two methods of selective potash mining using the "loading-unloading-dumping" technology are proposed. The economic effect at realization of recommended schemes is calculated.
This article presents an analysis of existing lava pillar excavation methods using selective mining implemented at the fourth potash horizon. A new method is proposed that ensures the recovery of not only economic resources but also non-commercial reserves of the fourth potash horizon. Non-commercial reserves are concentrated in the ninth sylvinite layer, which contains about 14% of the total resources of this horizon. The economic effect of the proposed mining method is up to $13 million for one mining pillar.
Mining of reservoir fields is associated with technogenic "perturbation" of a specific environment - a rock massif. This object is very complex in structure, different in mechanical properties and characterized by a wide variety of laws of change of its stress-strain state (SSS). Obviously, the study of parameters of mechanical processes in such media cannot be methodologically predetermined by the use of data only from full-scale experiments, or data only from laboratory studies or the results of analytical calculations.
Рассмотрен вопрос, связанный с исследованием характера восстановления нагрузки на почву лавы позади очистного забоя после выемки верхнего слоя в условиях Третьего горизонта ПО «Беларуськалий». Результатами натурных исследований подтверждены ранее полученные данные о наличии и местоположении зон пониженных нагрузок на почву лавы под отработанным пространством после выемки верхнего слоя. Разработаны мероприятия по предотвращению внезапных выбросов соли и газа из пород почвы горных выработок с использованием активных и пассивных способов.
On the example of the Starobino deposit, the criteria determining the choice of development systems and possible ways to increase potash recovery are considered. Various schemes for extraction of sylvinite from the pillars using drill-and-screw technology were proposed. A methodology of geomechanical substantiation of parameters of extraction of targets is developed. The results of evaluation of stress-strain state of the targets and the host massif for characteristic time moments of existence of the excavated spaces outlining the targets are presented.
The concept of local geological disturbances, type of plunge muldes, their nature and danger is presented. The existing and alternative ways of transition of geological disturbances by mechanized complexes are considered. The calculation of the cost of transition of geological disturbance in Microsoft Excel application is made, which allows to estimate with sufficient accuracy the losses from the meeting by the complex of the disturbance. A graph of the dependence of the disturbance transition on the radius of the hazardous zone has been constructed, according to which the rational zones of application of various methods of their transition have been determined. The analysis of modeling of geological disturbance transition on equivalent materials was carried out.
The paper describes the methodology of solving the problem of determining the degree of mutual influence of mining works on different horizons during the development of reserves of mine fields. By the example of mining three horizons of Starobinskoye deposit, the results of solving mining-geomechanical problems on the assessment of the stress-strain state (SSS) in the zones of influence of mined-out spaces of the salt massif are presented. The dependences for calculating the stress concentration coefficient at different configurations of the front of the development of mining works are proposed.
On the example of Starobinskoye deposit the criteria determining the choice of development systems and possible ways to increase the extraction of potassium reservoirs are considered. Different principal schemes of sylvinite extraction from pillars by auger drilling technology are proposed. The method of geomechanical justification of the parameters of pillar extraction is developed. The results of the estimation of the stress-strain state (STS) of pillars and their host massif for the characteristic time moments of the pillar delineation of mined-out spaces are given.
Statistical analysis of the results of crossing by mining works of geological disturbances of dip trough type at PA Belaruskali has been performed. I.A. Odessky's theory on formation of dip troughs is considered and specified. On the basis of the basic method, used in the mines of the Association and the described theory of mound formation, the method of artificial initiation of coal and gas blowout in the longwall at excavation of the Third Potash Seam of Starobinskoye deposit at full capacity was developed. Parameters of the method are determined taking into account the geometric structure of the dipping trough. Immediately before the initiation of drilling and blasting operations a conductive channel is formed for salt and gas ejection into the mined-out space. For the given method, taking into account geological structure of the troughs and physical and mechanical properties of salt rocks, a standard BWR passport for artificial initiation of salt and gas ejection with limitation of the ejection intensity is calculated. According to the passport, the blasting is carried out with three deceleration stages, at that the central borehole is not charged. The results of calculations of parameters of works on initiation of sudden emissions in zones of geological disturbances are presented.
The anchoring system used in the Soligorsk mines of the Starobinsky potash salt deposit and a new anchoring method using a variable-diameter borehole have been tested in various mining and geological conditions. Intense tangential stresses perpendicular to the anchor axis cause displacement of the rock layers; the backlash produced by drilling a variable diameter borehole will allow the rock layers to move horizontally without breaking the anchor rod. Thus, the service life of the anchoring is planned to be doubled. In order to reduce the cost of anchoring of mine workings with screw anchors it is proposed to reduce the length of anchors from 1.8 to 1.5 meters. At the same time, threading is not performed along the entire length of the rod, but only for the length of its anchoring in stable rocks (0.43 m). The possibility of using the new method of anchoring with the proposed parameters is confirmed by analytical calculations.
Рассмотрены особенности аварийных обрушений основной кровли при слоевой выемке Третьего калийного пласта. Проведен предварительный анализ горно-геологических условий их проявлений. Выявлены параметры непосредственной кровли, оказывающие влияние на интенсивность обрушения. С помощью критерия Фишера найден 'критерий динамичности', позволяющий оценить опасность различных участков шахтного поля.
