Physico-mechanical Properties Of Rocks Research Articles

Prediction of rock properties using grinding characteristics of ball mill

Knowledge of physico-mechanical properties of rocks is essential starting from the preliminary exploration to processing in mining projects. The strength properties of rocks considered necessary for mine planning and design, selection of equipment, use of suitable processing technique, etc. Sophisticated laboratory facilities are required to determine various properties of rocks using some international standards like ISRM, ASTM, etc., which is time consuming and costly affair. In this study, an attempt is to predict some of the rock properties like density, tensile strength using grinding characteristics of ball mill. Laboratory experiments conducted on samples of granite, limestone, slate and BHQ varying different parameters like quantity of feed, charge ratio, size of balls, grinding time, etc., at constant RPM of ball mill. Grinding characteristic curves used to obtain 25%, 50%, 80% cumulative passing sieve sizes. In addition, laboratory experiments carried out to find physico-mechanical properties like density, tensile strength, Protodyakonav's strength index, rebound hardness number. Regression analysis carried out with the data obtained from experiments.

Prediction of rock properties using grinding characteristics of ball mill

Knowledge of physico-mechanical properties of rocks is essential starting from the preliminary exploration to processing in mining projects. The strength properties of rocks considered necessary for mine planning and design, selection of equipment, use of suitable processing technique, etc. Sophisticated laboratory facilities are required to determine various properties of rocks using some international standards like ISRM, ASTM, etc., which is time consuming and costly affair. In this study, an attempt is to predict some of the rock properties like density, tensile strength using grinding characteristics of ball mill. Laboratory experiments conducted on samples of granite, limestone, slate and BHQ varying different parameters like quantity of feed, charge ratio, size of balls, grinding time, etc., at constant RPM of ball mill. Grinding characteristic curves used to obtain 25%, 50%, 80% cumulative passing sieve sizes. In addition, laboratory experiments carried out to find physico-mechanical properties like density, tensile strength, Protodyakonav's strength index, rebound hardness number. Regression analysis carried out with the data obtained from experiments.

ГЕОМЕХАНИЧЕСКАЯ ОЦЕНКА ПАРАМЕТРОВ УСТОЙЧИВОСТИ ОТКОСОВ БОРТОВ И УСТУПОВ ПРИ ОТРАБОТКЕ МЕСТОРОЖДЕНИЯ АПАТИТ-НЕФЕЛИНОВЫХ РУД «ОЛЕНИЙ РУЧЕЙ»

Актуальность обусловлена необходимостью безопасного ведения горных работ на карьерах глубиной свыше 360м. Наращивание объёмов добычи возможно при значительном углублении; для снижения объёмов вскрыши необходимо укручение откосов бортов и уступов. Для решения данного вопроса необходимо знать геомеханическую обстановку уступов и бортов как на предельном контуре, так и при изменении их основных параметров – высоты и углов наклона. Цель: проанализировать горно-геологические условия месторождения «Олений ручей» и существующие данные о физико-механических свойствах горных пород, слагающих массив рассматриваемого месторождения, произвести расчет и проверку устойчивости откосов бортов карьера на предельном контуре и изыскать возможность укручения откосов бортов и вскрышных уступов при ведении горных работ. Объект: крупное месторождение апатит-нефелиновых руд «Олений ручей». Методы: горно-геологический анализ месторождения «Олений ручей» и анализ существующих данных о физико-механических свойствах горных пород, слагающих массив рассматриваемого месторождения, аналитические расчеты устойчивости элементов откосов. Результаты. Получены данные расчетов устойчивости откосов при отсутствии поверхностей ослабления в прибортовом массиве борта в висячем боку рудной залежи (висячий борт) и с учетом угла падения Главного разлома под углом 40–45° при формировании борта в лежачем боку (лежачий борт), а также с учетом сейсмичности района и уровня грунтовых вод. Определены параметры откосов бортов на предельном контуре. Полученные значения параметров правомерны при отсутствии в прибортовом массиве поверхностей ослабления. При наличии поверхностей ослабления с падением в выработку откосы необходимо заоткашивать строго по этим поверхностям.

The Influence of the Physical and Mechanical Properties on the Abrasion Rate of Rocks Along Idfo-Marsa Alam, Eastern Desert, Egypt

The physico-mechanical properties of rocks have crucial influence on their abrasion rates. Therefore, the objective of this study is to investigate the rock properties that govern their abrasion resistivity. For that purpose, about 132 core specimens, of granite, marble, serpentine, and breccia, were extracted from two locations in Wadi El-Miah region in the vicinity of Idfo-Mars Alam Road, South-East, Egypt. Several laboratory tests were conducted to determine the relationships between abrasion resistance and physical (i.e. porosity, density and P-wave velocity) and mechanical (i.e. uniaxial compressive strength, tensile strength and surface hardness) properties of these rocks. Subsequently, statistical analysis was employed to derive equations for estimating abrasion rates based on physico-mechanical rock properties. The results showed that the abrasion resistance decreases with increasing uniaxial compressive strength, Brazilian tensile strength, Schmidt rebound hardness, P-wave velocity, and bulk density. It was also revealed that the abrasion rate increases with increasing effective porosity. Additionally, the derived equations showed good correlations between abrasion resistance and bulk density; Schmidt rebound hardness; and tensile strength (i.e. R2 = 0.72–0.84). Thus, they can be successfully used to predict the abrasion rates. Hence, rock abrasion rate could be adopted as a tool to sort out stones for proper industrial purposes (i.e. flooring, heavy traffic, decoration, construction, building, etc.).

Multiple regression model for prediction of rock properties using acoustic frequency during core drilling operations

ABSTRACT The primary purpose of this study is the quantification of rock properties uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), density and abrasivity, using sound signal dominant frequencies produced during diamond core drilling operations. Rock drilling operations were performed on seven different types of rock samples, using a computer numerical control (CNC) drilling machine. Using the multiple regression analysis, satisfactory mathematical equations were developed for various physico-mechanical rock properties, as well as dominant frequencies of the sound level were generated during diamond core drilling operations. The developed prediction models demonstrated a good regression coefficient between the rock properties and dominant frequencies i.e. the R2 values are 82.50%, 78.41%, 79.40%, and 93.24% for UCS, BTS, density and abrasivity, respectively. The performances indices are: (i) root-mean-square error (RMSE) are 0.102754, 1.241652, 0.396727, and 0.697889 for UCS, BTS, density and abrasivity, respectively; (ii) values account for (VAF) is 82.50008%, 78.41137%, 79.40137%, and 93.23596% for UCS, BTS, density and abrasivity, respectively. Presently, it is in the early stages of development towards the prediction of rock properties using dominant frequencies with the help of audio signal processing in the rock drilling operation. The developed prediction models can be utilised at the early stages of mining and civil engineering projects, for the quantification of rock properties using sound signal dominant frequencies.

Substantiation of Stable Pitwall Parameters Based on the Mining Rock Mass Rating

A set of geomechanical studies is carried out to justify the angles of stable slopes in the Dzhetygarinsky open-pit mine, including testing the physico-mechanical properties of rocks, studying the structure of adjacent rock mass, determining the values of the mining rock mass rating (MRMR) and zoning the open-pit surface according to Professor Laubscher’s classification. The values of slope angles of open-pit benches are recommended, and the measures to ensure their stability are developed. The factors affecting the adjacent rock mass most negatively are identified in classifying the rocks of open-pit mine surface. It is found that the effect of certain factors can be significantly reduced, which allows increasing the values of pitwall control angles while maintaining the proper degree of mining safety.

Effects of the physico-mechanical properties of low-strength pyroclastic rocks on cutter wear of roadheaders

Construction projects that use mechanical excavators such as tunnel boring machines (TBM) or roadheaders generally result in high costs due to cutter wear. Cold storage caverns (CSC) are one area where roadheaders are used, but excavations of CSCs show different characteristics than tunneling and mining excavations. The effects of the physico-mechanical properties of low - strength, pyroclastic rocks (tuffs) on the wear of roadheader cutters were investigated during the excavation of CSCs in the Cappadocia region of Turkey. The excavated tuffs containing 13–19% quartz had low uniaxial compressive strength (UCS), ranging from 3.14 to 13.17 MPa. Field excavation performance parameters were continuously recorded for one week on two similar roadheaders and 14 different CSCs projects. The average field cutter consumption rate (CCRField), defined as cutter material loss per excavation of 1 cubic meter rock, was calculated for each CSC. Physico-mechanical tests were performed on the rock samples collected from the CSC project areas. Additionally, sieve analyses were performed on the excavated rock materials to determine their coarseness index (CI) and mean particle size (d(50)). The calculated average CCR values were statistically analyzed with some physico-mechanical properties of rocks, in-situ Schmidt hammer hardness (SHHIn-situ), CI and d(50). Negative correlations were found between CCR and each of the UCS values, Brazilian tensile strength (BTS), point load strength (Is(50)), SHHIn-situ, CI and d(50), and a positive linear correlation was found only with the water contents of the rocks. All of these relationships were found to be dependent on crushing of the excavated materials in fine sizes, blockage of cutters by filling of the fine materials into the space between the holder and cutters and adherence of fine materials to the cutters and cutterhead, as affected by water/moisture and clay contents. This study, whose results apply to studies in the Cappadocia region of Turkey, showed that the CCRField of roadheaders decreased as the strength of rocks increased. These relationships specifically apply to easy-cutting tuffs with very low strength and high water content.

Quantification of Rock Properties Using Frequency Analysis During Diamond Core Drilling Operations

Rock drilling is one of the most essential operations in mining and allied industries. This study focuses on the quantification of physico-mechanical rock properties using dominant frequencies from the sound signal generated through diamond core drilling operations. The rock drilling experiments were performed on five different types of rock samples using a computer numerical control drilling machine. Using simple linear regression analysis, satisfactory mathematical equations were developed between various physico-mechanical rock properties, namely, uniaxial compressive strength, Brazilian tensile strength, density and dominant frequencies of sound level were generated during diamond core drilling operations. The developed models can be utilised for quantification of rock properties with an acceptable degree of accuracy in realistic applications.

DETERMINATION OF WATER ABSORPTION PROPERTIES OF NATURAL BUILDING STONES AND THEIR RELATION TO POROSITY

It is known that rock-water interaction has important effects on the physicomechanical properties of rocks. In this study, 20 rock with different origins were used. The water absorption properties of rocks were determined by immersion and capillarity-effected water absorption experiments. The rocks are classified according to the water absorption properties of the capillary effect. The relationships between water absorption properties and porosity properties of rocks were evaluated by regression analysis. The results obtained are given in the form of regression equations.

Features and regularity of zonal changes in the physicomechanical characteristics of Zakhidnyi Donbas rocks

This article summarizes the results of numerous experimental studies of the physicomechanical properties of rocks from deposits of Zakhidnyi Donbas. The analysis of the obtained data allowed us to reveal the zonal nature of their change. Regularity has been established for increasing the strength parameters of rocks in the direction from west to east, the mechanism of which is explained, among other things, by the influence of Coriolis forces arising from the daily rotation of the Earth. It has been established that for more durable rocks, such as sandstone, the change in strength characteristics in the roof and floor is insignificant, whereas for weaker mudstones and siltstones, there is a significant difference in the above strength parameters. A generalization of the test results of Zakhidnyi Donbas rocks showed a large variation in their properties under the conditions of the achieved depth of the reservoir under development, which is due to the variability of the composition, structure, texture of the rocks and the degree of epigenetic transformations.

Investigation of the effect of physico-mechanical properties of rocks on drillability

Investigation of the effect of physico-mechanical properties of rocks on drillability

Water Saturation Influences on Engineering Properties of Selected Sedimentary Rocks of Pakistan

This study is focused on the evaluation of water saturation influence on the mechanical and physical properties of 34 sedimentary rock units selected from different geological formations in Pakistan. The laboratory testing program comprised the determination of physico-mechanical rock properties of both air-dry as well as fully water saturated rock specimens. Further thin section analyses of all rock samples were also performed to explain their petrography. According to the statistical analyses overall reductions of around 40 and 50% were found in UCSsat and BTSsat values, respectively, measured on saturated rock samples in comparison to their corresponding dry strength values, i.e. UCSdry and BTSdry. Linear correlations were found between ultrasonic wave velocities as well as density of both dry and saturated rock samples. In addition, the dry and saturated UCS values were exponentially related with the rock porosity. Multiple regression technique was also utilized to develop a predictive linear model of UCSsat with geotechnical rock properties in the dry condition and petrographical characteristics of rock samples. Finally the validity of multiple regression model developed in this study and an existing correlation for the conversion of UCSdry into UCSsat was statistically assessed.

Influence of physico-mechanical properties of Indian dimension stones on cutting rate of diamond wire saw

Cutting performance of diamond wire saw is a key factor influencing mine planning, production scheduling, and equipment selection for dimension stone quarries. It is normally measured in terms of cutting rate. Rock samples collected from various granite and marble quarries in India were tested in laboratory to determine their physico-mechanical properties. Cutting rate of diamond wire saw was measured in the field studies during the actual cutting process in quarries. Using these laboratory determined properties and the cutting rate, a multiple linear regression model has been developed to predict the cutting rate of diamond wire saw. Physico-mechanical properties of rocks determined in laboratory are used as independent variables and cutting rate as predictor variable in the regression model. The study indicates that the cutting rate increases with a decrease in most of the hardness and strength parameters of rock. The final model is tested for its goodness of fit indicating a significant linear relation between cutting rate and physico-mechanical properties, namely tensile strength, slake durability index, and Cerchar hardness index with regression coefficient of 94%. The resulting model can be used suitably for different types of hard to medium hard and soft dimension stones. The generalized model for estimating the cutting rate becomes a handy tool for mining engineers to work out operating efficiency, expenses, planning etc. of the dimension stone block cutting.

Технологические способы ведения взрывных работ, позволяющие безопасно управлять действием взрыва в массиве горных пород

Purpose. The work is devoted to improving the efficiency and safety of the escarpous blasting of rocks by borehole charges of explosives of a new design at iron ore quarries. In the thesis, the features of the process of explosive destruction of rocks by well charges of various designs are investigated. The dependences of their dynamics of explosive destruction on the physicomechanical properties of rocks are established, and the relationship between the distribution of energy of destruction in the medium and the magnitude of the specific impulse of the explosion is determined. Metodology. The obtained regularities of the impulse effect of an explosion associated with the overall energy balance imparted to a destructible medium can serve as a scale for evaluating the effectiveness of the action of well charges exploded simultaneously or through the definition of deceleration. Based on the obtained theoretical and laboratory results, a new design of a downhole charge of explosives with an air cavity in the bottom of the well has been developed. Findings. A feature of this design of the borehole charge is the concentration of the explosion energy in the bottom of the well. The optimal parameters of the air cavity and the location of the initiator relative to it in the technology of blasting have been established. Originality of the work lies in the fact that the conducted industrial tests of a new design of a borehole charge with an air cavity in the bottom part of the well showed its high efficiency. Practical value lies in achieving a reduced specific consumption of explosives. This technological process ensures uniform crushing of the blasted rock mass over the entire height of the ledge and high-quality development of the bottom of the ledge, which opens up real opportunities for the elimination of the re-drilling of the well at the inferior explosive blasting of rocks.

A study to correlate LCPC rock abrasivity test results with petrographic and geomechanical rock properties

Rock abrasivity is very much influenced by the petrographic and physico-mechanical properties of rock and hence its assessment from common geomechanical rock properties is helpful for rock engineers in estimating excavation costs. In this paper LCPC and CERCHAR abrasivity tests, as well as a complete suite of mechanical and physical rock properties tests, were conducted on 51 rock samples collected from different locations in Pakistan. Moreover, petrographical studies of 48 rock specimens were performed along with the computation of Schimazek's F-value (F-value) and Rock Abrasivity Index (RAI). For the analysis of test results least square regression was employed. Initially the LCPC abrasivity coefficient (ABR) values were correlated with CERCHAR abrasivity index tests and reasonable relationships were observed. Statistically meaningful relationships were found between ABR and geotechnical wear indices (F-value and RAI). Possible correlations of LCPC test results with rock properties are also discussed. Finally multiple regression analysis was applied to find statistically significant correlation of ABR with petrographical and physico-mechanical rock properties. Test results show that RAI, Brazilian tensile strength and mean quartz grain size (Ø-qtz) prove to be the statistically best predictors of ABR from the rock properties determined. The developed correlations are specifically intended for rock engineers involved in designing excavation projects.

An experimental investigation on the durability of railway ballast material by magnesium sulfate soundness

In this study, the durability of railway ballast material is investigated by magnesium sulfate soundness tests. Two types of ballast aggregates, which are produced from basaltic rocks and currently used as railway ballast in such high speed railway routes in Turkey, are investigated regarding their resistance against freezing–thawing (FT) and traffic loads. Firstly, the mineralogical and physico-mechanical properties of rocks are determined. Then the degradation of investigated ballast aggregates is determined by magnesium sulfate soundness and Los Angeles abrasion (LAA) tests. The natural FT effects are simulated by magnesium sulfate soundness tests up to 40 cycles, whereas the traffic loads are represented by LAA tests up to 3000 revolutions. The ballast fouling that leads to such problems are also investigated within the scope in the present study. The degree of ballast fouling is quantified as fouling index (FI) which is determined using the crushed particles generated after LAA tests. It is concluded from laboratory studies that rock properties considered are considerably influenced by simulated FT cycles. It is also achieved from the laboratory studies that magnesium sulfate soundness and Los Angeles abrasion tests are good indicators to clarify the fragmentation mechanism of the ballast aggregate in laboratory scale. In conclusion several empirical formulas are developed to predict LAA and FI for each rock type. The proposed empirical formulas could be utilized as a pre-design tool for new railway routes in design stage provided that the investigated ballast aggregates are considered.

Engineering Geological and Geotechnical Investigations for a Pump House Complex Site — a Case Study from Lift Irrigation Scheme

ABSTRACT For the deep underground pump house complex engineering geological and geotechnical investigations were carried out. The area was investigated through detailed engineering geological mapping, exploratory drilling, in-situ stress measurements and laboratory testing. Surface mapping was done on 1:500 scales with 0.5 m contour interval and drill holes logging was done on 1:100 scale. The rock mass properties, i.e. joint sets, weathering grade, RQD etc. of the rock masses to be encountered during the excavation of cavities have been analyzed in detail. Core samples from the exploratory drill holes drilled at the surge pool and pump house area were tested for physico-mechanical properties of rocks in the laboratory. To evaluate the stress regime at the proposed underground pump house complex area, stress measurements were carried out by hydrofracturing method inside the borehole. The mapping details indicated that cavities will be excavated through fresh, coarse to very coarse grained, hard and jointed granites. The average depth recorded of fresh rock from the surface was 15.7 m. The uniaxial compressive strength of the rock mass range from 221 to 246 MPa. The orientation of the long axis of the cavities recommended is N150°. Classification of rock mass using Tunnelling Quality Index Q is attempted and the values are range from 3.58 to 16.40.

Якост на точково натоварване на гранодиорити от Планския плутон

The studied area is located in the southeast parts of the Plana Mountain. It is built up of Plana diorite pluton, represented by granodiorites, quartz-diorites and quartz-monzonites, which is located among the older (Precambrian) metamorphic rocks (gneisses, amphibolites, schists and fillites). Plana Pluton is part of Tsentralnosrednogorska magmatic province. The aim of the present work is to clarify the physico-mechanical properties of rocks from the Plana pluton in the area of village of Gorni Okol. For this purpose the values of Point load strength index Is(50), water absorption, bulk density, etc. are determined. Correlation dependencies between the studied parameters are revealed.

Interconnection of structural features and physico-mechanical properties of rocks

Interconnection of structural features and physico-mechanical properties of rocks

Indirect estimation of electrical resistivity by abrasion and physico-mechanical properties of rocks

This paper attempts to estimate electrical resistivity from physico-mechanical and abrasion properties of rocks. For this purpose, the electrical properties of rock samples collected from igneous and metamorphic formations were initially measured in a laboratory by employing the two-electrode method. In addition, physical, mechanical, and abrasion properties of the rocks were determined. Then, an attempt was made to examine the possibility of estimation of electrical resistivity from other rock properties.In this sense, it was found that water content, porosity, and the ratio of Vp/Vs have significant effects on the electrical resistivity. Moreover, we report that indirect tensile strength and static elastic modulus indirectly control the electrical characteristics of rocks, since reasonable correlations exist between them. Nevertheless, the reliability of the effect of rock abrasion on the resistivity could not be confirmed with a high degree of certainty. More data are needed to check its validity. Thus, we conclude in light of statistical analyses that the results of the tests and the relationships are statistically significant. For this reason, the electrical resistivity of the intact rock can be indirectly estimated by accounting for the physico-mechanical properties for a given formation. However, rock abrasion cannot be considered for the same purpose.