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The article presents the second part of the results of asymmetrical disc tools laboratory tests. The first part of this study was presented at SGEM International Conference in 2017. Asymmetrical disc mining tools can be used for mechanical mining of hard rocks, as an alternative to blasting methods. The study was conducted on a dedicated laboratory stand, with an installed drive power of 80 kW. Stand consists of rotating rock sample, mined by special plate equipped with asymmetrical disc tools by a so-called undercutting method. The quantitative research was based on mass measurements of discs before and after mining the rock sample. On this basis, for each of tested disc, a wear factor was specified. Moreover, during the tests thermal measurements (using thermography camera) were made; the results of those, using thermoelastic theory, were compared with load measurements (using standard strain gauge meters). The findings from conducted research may help in the selection of the optimal tool for mechanical hard rock mining using an undercutting method, as well as to make estimates of the wear of disc tools. A thermal analysis could be used in further research to analyze the tool material behavior during the mining process. [ABSTRACT FROM AUTHOR]

Great problem of mechanical hard rock mining is low durability of mining tools. In Department of Mining, Dressing and Transport Machines, AGH UST in Cracow new solutions of mining tools and their holders were developed. In paper, a special tool to replace traditional rotary pick (so called crown-shaped pick), new lubricated holder for rotary-tangential picks, asymmetrical disc cutters, results of laboratory, field and industrial tests were described. Crown-shaped pick has the same type of handle as standard solutions, the difference lays in cutting segment which is consisted of truncated cone shape with 7 - 8 carbide inserts in the cutting edge. Such construction allows increasing number of pick turnovers. Also, the improving of pick working conditions in holder was main reason for developing of lubricated holder for rotary-tangential pick. This solution allows to supply of emulsion between pick handle and internal surface of holder, what results in symmetrical wear of cutting edge and increases lifetime of the tool. The results of laboratory tests, as well as first field tests using roadheaders and elaborated new conception of lubricated crown tool were presented. [ABSTRACT FROM AUTHOR]

The article presents the results of asymmetrical disk tools laboratory tests. This type of mining tools can be used for mechanical mining of hard rocks, among others in the solution of innovative roadheader head, presented on SGEM conference in 2016. The study was conducted at a dedicated laboratory stand, with an installed drive power of 80 kW. Stand consists of rotating rock sample, mined by special plate equipped with asymmetrical disk tools. The rock is mined using undercutting technique, also known as Wohlemyer method, after the name of its Austrian researcher. During research six components of the load acting on the disc plate were measured; in addition to this, thermographic observations were conducted. Tools have been tested in both qualitative and quantitative ways. Qualitative research consisted of disc measurement using 3D scan both before and after the mining test. After comparison of the corresponding three-dimensional images of discs and performing measurements with the appropriate computer software, image of individual tools wear were obtained. The results of quantitative research were based on gravimetric measurements of disks before and after the tests. The findings from conducted research may help in selection of the optimal tool for mechanical hard rock mining using undercutting, as well as to make estimates of the sustainability of individual disc tools. [ABSTRACT FROM AUTHOR]

Drilling rigs are one of the most primary equipment of the underground mining industry. Thanks to their application, it was possible to multiply several times obtained metal ore output generated in underground mines. For last several years, the research related to the development of special rigs predisposed to mine narrow vein deposits are conducted. Dynamic testing of one of such structures are discussed in the paper. The dynamic tests of the rig have been carried out in two ways - either as a real construction study, involving full size rig passing through the obstacle and analysis of measurement results, as well as the simulation study. A comparison of these two methods can determine the extent in which carried out simulations coincide with reality. The parameters measured on the construction elements, both in the real and computer tests, were three dimensional accelerations. On this basis the values of dynamic forces acting on the structure were calculated, as well as the points in which the construction was heavily loaded and is most vulnerable to destruction were estimated (using FEM analysis). The paper refers to the virtual models of drilling and bolting rigs presented at the SGEM 2016 conference. The presented research methodology will allow to minimize the cost of design of machines and increase their reliability, which translate directly into miners work safety. [ABSTRACT FROM AUTHOR]

The paper presents the set of two innovative types of machines dedicated to work in hard rock mining, especially in narrow veins. First machine is a single boom drilling rig, and the second a roof bolter equipped with special mesh handler. The paper shows the design methodology of both of these machines, with particular emphasis on usage of computer simulations in design process. The boundary conditions for design and simulations were based on the identified mining circumstances connected with exploitation of narrow vein deposits. Simulation tests included the kinematic and dynamic verification of both chassis and working system (drill or bolter). An important element of the study have been the verification of chassis design in terms of passing through obstacles (thresholds). The study used a multibody simulation method for analyzing each of the rigs structure. The article presents the adopted physical model of the objects, as well as the results in the form of loads acting on individual components of the car, which allows to conduct virtual verification of their construction. As a conclusion of conducted studies, final constructions for each of the machines are presented. [ABSTRACT FROM AUTHOR]

Today, majority of Ukrainian mining companies realized that the production yield of suitable for sale blocks using explosions method constitutes not more than 30%. It can be increased up to 80 % by means of using modern equipment for stone extraction, this method is proved to be effective granite extraction. Diamond-sawing rope belongs to such equipment. Techniques for soft and solid rock extraction have significant differences. For example, diamond wire can be used with stone-cutting machines (bar, ring or circular saws) in extraction of soft rocks. Whereas, drilling equipment and gas burners are traditionally used in the hard rock mining. There are a lot of different technological nuances in mining solid rocks by diamond-wire saws. The publication describes the main options for separating natural stone monoliths from an array using the diamond-cable technology in granite quarries of Ukraine. The losses and waste with are created in the result of separation of stone monoliths, from an array using diamond-tipped ropes, are calculated. [ABSTRACT FROM AUTHOR]

The authors have formulated general principles of organization of a typical integrated complex geomechanical monitoring system under conditions of hard hierarchicallyblocked rock massifs at gravity-tectonic field of natural stress state. It has been shown that a principal task for geomechanical monitoring is studying of mining-engineering "facility-rock massif" systems state and fixation of its spatial and time changes. At that, the main final purpose is to design a general geomechanical model for the naturalengineering system under study which could be used to solve different geomechanical tasks. The authors have defined working stages implementation of which is obligatory when creating the integrated geomechanical monitoring system. A case study of the geomechanical monitoring system installed in JSC Apatit mines was performed and trends in its further improvement were marked. [ABSTRACT FROM AUTHOR]

The article presents an innovative solution of roadheader mining head developed at the Department of Mining, Dressing and Transport Machines, AGH University of Science and Technology in Krakow, as an alternative for standard roadheader mining units. The general idea behind the new mining solution was to use so called undercutting or Wohlmeyer Method, using asymmetrical disc tools moving with complex motion trajectory. This approach gives an opportunity efficiently mine hard rocks using roadheader type machines. Advantages of the applied mining method, design process stages, as well as the results of preliminary tests were described in paper. After theoretical analysis of the hard rock mining process using asymmetrical disc tools, series of laboratory tests were conducted, allowing to determine the guidelines for a construction of a roadheader head prototype. This have been the basis for development of technical project of a new head solution adapted for mounting on the arm of a medium roadheader R 150, constructed by Famur Ltd Company from Katowice, Poland. A constructed head was tested on a research field stand - specially prepared cubic concrete block with increased strength parameters. Positive tests results were obtained, which indicates the potential and possibility of industrial application of such solution in mining and underground construction industry. [ABSTRACT FROM AUTHOR]

Determining the rock mass state with in-situ methods takes an important role for the research. To the date, broad experience has been accumulated in experimental determinations of geomechanical setting in the Russian north-western ore open-pits. It is the Zhelezny mine open-pit, JSC Kovdorskiy GOK, which seems to be the most studied among the others. The paper presents findings of geophysical research of the rock mass mechanics state. The results are given on determining stress-strain state and velocity models of the open pit wall section monitored by the seismic-tomographic method. The important role of geophysical control methods is shown when rock mechanics state assessing in the open pit wall. [ABSTRACT FROM AUTHOR]

Estimation of blasted rock fragmentation is of great importance in hard rock mining. There are many, mostly empirical or semi-empirical, models for its estimation. New theoretical model for estimating fragmentation of blasted rock is proposed in this paper. Model is based on theoretical research in rock breakage by explosives. Conducted research resulted in new rock breakage theory that made possibility of estimating tension crack density and radii of fragmenting zones. Utilizing these theoretical results with assumption that prior blasting quasi-isometric fragments are formed it is explained how blasted rock fragmentation could be estimated. Also, it is shown how structural properties of rock mass impact rock blasting and its fragmentation. Example is given, at the end of the paper, where it is explained how rock fragmentation could be estimated using geometrical analysis. [ABSTRACT FROM AUTHOR]