Saliferous Rocks Research Articles

Методика прогноза напряженно-деформированного состояния крепи вертикального ствола на участке сопряжения с горизонтальной выработкой в соляных породах

The article proposes a method for predicting the stress-strain state of the vertical shaft lining in saliferous rocks at the drift landing section. The paper considers the development of geomechanical processes in the saliferous rock in the landing area, the support is viewed as a two-layer medium: the inner layer is concrete, the outer layer is compensation material. With this in view, the paper solves the problem of continuum mechanics in a spatial setting, taking into account the long-term deformation of salts and the compressibility of the compensation layer. Long-term deformation of saliferous rocks is described using the viscoplastic model of salt deformation into the numerical model, and the crushable foam model to simulate the deformation of the compensation layer. This approach considers all stages of the deformation of the compensation layer material and the development of long-term deformations of saliferous rocks, which makes it possible to increase the reliability of the forecast of the stress-strain state of the vertical shaft lining.

Методика прогноза напряженно-деформированного состояния крепи вертикального ствола на участке сопряжения с горизонтальной выработкой в соляных породах

Методика прогноза напряженно-деформированного состояния крепи вертикального ствола на участке сопряжения с горизонтальной выработкой в соляных породах

Protection of mine bins in saliferous rock mass of potash mines

Protection of mine bins in saliferous rock mass of potash mines

Теоретические исследования механического состояния соляных пород

Теоретические исследования механического состояния соляных пород

Monitoring the Stress-Strain State of Marginal Saliferous Rock Mass

To reduce the risk of accidents in underground deposits of water-soluble ores, a flexible system of geomechanical monitoring of mine safety is required. Many years of experience in studying the physical and mechanical properties and stress-strain state of saliferous rocks when mining sylvinite layers in the mines of the Upper Kama potash salt deposit has made it possible to develop the principles of experimental and theoretical evaluation related to the load-carrying elements of the mining system. The essence of this method lies in the meaningful interpretation of the results of in situ studies using mathematical modelling.

Mechanism of Scale Effect in Saliferous Rock Under Compression

According to the results of compression experiments on different types of sylvinite and rock salt samples, it has been established that the second-class scale effect is basic for quasi-plastic saliferous rocks; the effect mechanism is based on a destructive high-plastic surface layer that is formed during the production of a specimen and increased during testing. Analytical formulas of the connection between true rock properties and the mechanical indicators of prismatic samples are given.

Газоносность соляных пород калийных месторождений Жилянское и Сатимола (Казахстан)

Газоносность соляных пород калийных месторождений Жилянское и Сатимола (Казахстан)

On inhomogeneous straining in compressed sylvinite

Spatiotemporal distributions of local components of the distortion tensor of quasi-plastic materials—saliferous rocks (sylvinite)—have been studied under active compressive straining conditions using double-exposure speckle photography techniques. The strain localization patterns are presented and the features of macroscopic strain inhomogeneity are considered for inelastic behavior of the material. Results obtained for the slow wave processes in deformed saliferous rocks are compared to analogous data available for ionic crystals.

Specific features of the formation of elementary sedimentary rhythms of rock salt in facies zones of the Permian halogenic basin of the Caspian region

Based on the composition of brine inclusions in halite, the formation conditions of elementary sedimentation rhythms of rock salt were determined in facies zones of the Permian halogenic basin of the Caspian region. The distribution of structural types of halite was analyzed and the rate of brine condensation was estimated by calculating the K+ concentration coefficients during the precipitation of 1 m rock salt (K1 g/l/m) and one elementary rhythm (K2 g/l/rhythm). It was established that the rock salt of the Karpensk and Lugovsk rhythmic beds (hereafter, rhythmites) at the base and middle part of the halogenic sequence of the Baskunchak structure precipitated in a relatively deep-water lithofacies zone at a constant influx of NaCl-saturated brine and its slow condensation. This is reflected in insignificant variations of the thickness of elementary rhythms. In troughs at the northwestern framing of the depression, rocks salts of the Privolzhsk and partially, Lugovsk rhythmites were precipitated without the condensation of brine owing to the partial dissolution of halite in the coastal zones of the basin. The anomalously thick elementary rhythms (up to 30–40 cm) were composed of coarse-crystalline and water-transparent feather halite deposited at the bottom. A rapid condensation of brine was also noted during the precipitation of rock salt underlying the K-Mg saliferous rocks in the troughs. In this area, the brine experienced density stratification, with the influx of both condensed brine from the central part of the basin and less dense brine from the inlet.

Metasomatism and ore formation at contacts of dolerite with saliferous rocks in the sedimentary cover of the southern Siberian platform

The data on the mineral composition and crystallization conditions of magnesian skarn and magnetite ore at contacts of dolerite with rock salt and dolomite in ore-bearing volcanic—tectonic structures of the Angara—Ilim type have been integrated and systematized. Optical microscopy, scanning and transmission electron microscopy, electron microprobe analysis, electron paramagnetic resonance, Raman and IR spectroscopy, and methods of mineralogical thermometry were used for studying minerals and inclusions contained therein. The most diverse products of metasomatic reactions are found in the vicinity of a shallow-seated magma chamber that was formed in Lower Cambrian carbonate and saliferous rocks under a screen of terrigenous sequences. Conformable lodes of spinel-forsterite skarn and calciphyre impregnated with magnesian magnetite replaced dolomite near the central magma conduit and apical portions of igneous bodies. At the postmagmatic stage, the following mineral assemblages were formed at contacts of dolerite with dolomite: (1) spinel + fassaite + forsterite + magnetite (T = 820−740°C), (2) phlogopite + titanite + pargasite + magnetite (T = 600–500°C), And (3) clinochlore + serpentine + pyrrhotite (T = 450°C and lower). Rock salt is transformed at the contact into halitite as an analogue of calciphyre. The specific features of sedimentary, contact-metasomatic, and hydrothermal generations of halite have been established. The primary sedimentary halite contains solid inclusions of sylvite, carnallite, anhydrite, polyhalite, quartz, astrakhanite, and antarcticite; nitrogen, methane, and complex hydrocarbons have been detected in gas inclusions; and the liquid inclusions are largely aqueous, with local hydrocarbon films. The contact-metasomatic halite is distinguished by a fine-grained structure and the occurrence of anhydrous salt phases (CaCl2 · KCl, CaCl2, nMgCl2 · mCaCl2) and high-density gases (CO2, H2S, N2, CH4, etc.) as inclusions. The low-temperature hydrothermal halite, which occurs in skarnified and unaltered silicate rocks and in ore, is characterized by a low salinity of aqueous inclusions and the absence of solid inclusions. The composition and aggregative state of inclusions in halite and forsterite indicate that salt melt-solution as a product of melting and dissolution of salt was the main agent of high-temperature metasomatism. Its total salinity was not lower than 60%. The composition and microstructure of magnetite systematically change in different mineral assemblages. Magnetite is formed as a result of extraction of iron together with silicon and phosphorus from dolerite. The first generation of magnetite is represented by mixed crystals, products of exsolution in the Fe-Mg-Al-Ti-Mn-O system. The Ti content is higher at the contact of dolerite with rock salt, whereas, at the contact with dolomite, magnetite is enriched in Mg. The second generation of magnetite does not contain structural admixtures. The distribution of boron minerals and complex crystal hydrates shows that connate water of sedimentary rocks could have participated in hydrothermal metasomatic processes.

Isotopic signatures of deposition and transformation of Lower Cambrian saliferous rocks in the Irkutsk Amphitheater: Communication 3. Carbon and oxygen isotopic compositions in carbonates

In previous communications based on the study of sulfur and strontium, we showed that Lower Cambrian rocks of the Irkutsk Amphitheater underwent a significant epigenetic transformation. All postsedimentary alterations of rocks are related to the influence of water solutions that provoke the direct (physical) dissolution of material and its chemical transformation. In particular, an appreciable portion of anhydrites disappeared from the section due to reduction. Probably, these processes took place several times in the past and they are continuing at present. A similar conclusion was deduced from the strontium isotopic composition of carbonate rocks. Their strontium isotopic composition is usually shifted relative to the primary composition, although the prevalence of sulfate and carbonate rocks in the section promotes the stability of strontium isotopic composition with respect to secondary alterations. The carbon isotope system is even more stable due to the abundance of carbonate rocks in the section. This circumstance is probably responsible for the incapacity of isotope data to serve as obvious evidence of the epigenetic transformation of carbonates. The major elements of the evolution of carbon isotope signature could be retained since the sedimentation stage.

The origin of dolomite associated with salt diapirs in central Tunisia: Preliminary investigations of field relationships and geochemistry

Black and white dolomite crystals (mm to cm width) of different isotopic composition are associated with Triassic diapirism in central Tunisia, as well as with evaporite minerals and clays. The white dolomites occur mostly in the Jabal Hadifa diapir near the contact with Cretaceous limestones, whereas the smaller black dolomites occur in the Jabal Hamra diapir. The former dolomite has a narrow range of δ 18O and δ 13C values (− 3.83‰ to − 6.60‰ VPDB for δ 18O; − 2.11‰ to − 2.83‰ VPDB for δ 13C), whereas the latter dolomite has a wider range and more depleted values (− 4.92‰ to − 9.97‰ for δ 18O; − 0.55‰ to − 6.08‰ for δ 13C). However, the 87Sr / 86Sr ratios of most of the samples are near Triassic seawater values. Dolomite formation is due to at least two different fluids. The main fluid originated from deeper hydrothermal or basinal sources related to the Triassic saliferous rocks and ascended through faults during the diapiric intrusion. The second, less important fluid source is related to meteoric water originating from Cretaceous rocks.

Mathematical modeling of pressure on the strengthening vertical shaft support in “Mir” mine located in the Charsk saliferous rock series

The problem statement and the solution algorithm are presented for the case of contact between strengthening vertical shaft support and rocks. Hereditary viscoelasticity equations are used as constitutive relations for saliferous rocks. An analysis of the dynamics of the growing pressure on the support is performed versus the shaft cross-section occurrence depth, saliferous rock strength on the contact, and spacing between the rock contour and the support in the shaft.

Isotopic signatures of deposition and transformation of Lower Cambrian saliferous rocks in the Irkutsk amphitheater: Communication 1. Sulfur isotopic composition

New isotope data on Lower Cambrian rocks of the Irkutsk amphitheater are reported in three communications. The first communication is devoted to the sulfur isotopic composition, which is most sensitive to ostsedimentary geochemical transformations of sulfate rocks in saliferous formations. It is shown that δ34S values in Bel’sk and Zhigalovo boreholes are within 22–35‰ The lowest values are close to the sulfur isotopic composition of a halogenic basin, while the highest values are related to epigenetic sulfate reduction. This process was responsible for the elimination of 100 m of anhydrites from the Lower Cambrian section.

Mathematical Modeling of the Stress-Strain State in Rock and Artificial Masses During Slice Chamber Mining of Underpit Reserves in the “Internatsionalnaya” Kimberlite Pipe

The statement and solution algorithm are proposed for the problem on the stress-strain state of a kimberlite body, filling massif, and enclosing rock during slice chamber mining with filling. The equations of nonlinear hereditary viscoelasticity are used as the constitutive relations for saliferous rocks.

Multistage Alterations of Pre-Vendian Oil-Bearing Rocks of the Baikit Anteclise (Siberian Platform) Based on Rb–Sr and K–Ar Data

Riphean carbonate rocks of the Baikit Anteclise with hydrocarbon raw material reserves exhibit a complicated block structure. Therefore, correlation of sections of even adjacent wells and general understanding of the geological structure of the territory are extremely hampered. The problem becomes more complicated because of multiple epigenetic reworking of Riphean rocks. Study of Rb–Sr and K–Ar systems based on materials from three boreholes drilled on the Baikit Anteclise reveal at least three stages of such reworking dated at about 1400, 1000, and 700 Ma, respectively. Rocks of the whole penetrated pre-Vendian section are assumed to be Early Riphean or even pre-Riphean. Brines saturating them are likely to be related to Vendian–Cambrian saliferous rocks.

Experimental Investigation of Saliferous Rock Properties by Impact Loading Method

Physical and mechanical properties of saliferous rocks are analysed using method of impact strength, which makes it possible to estimate their mineralogical composition.

Subsidence problems in route design and construction

Summary The paper reviews the main causes of ground subsidence as it affects route design and construction in the United Kingdom. Investigation techniques and remedial measures are discussed in relation to both natural and mining subsidence. In addition to the common occurrence of subsidence problems in the coalfields, emphasis is placed on their presence elsewhere in the country. Natural subsidence problems are associated mainly with carbonate and saliferous rocks but mining activity has taken place at various times at numerous geological horizons for a variety of minerals. Future mining activity is likely to involve fewer minerals but will still be dominated by the coal industry. Experience has shown that the conflicting interests of route planners and mineral operators can usually be resolved by negotiation, accompanied in some cases by compensation.

On the saliferous rocks and salt springs of Michigan

On the saliferous rocks and salt springs of Michigan

Equivalent formation, in England, of the “saliferous rock” of North America

"Equivalent formation, in England, of the “saliferous rock” of North America." The Philosophical Magazine, 6(31), pp. 75–76