The article describes the main areas of research in the field of the explosive destruction of rocks used in mining. The results of studies carried out in recent years are presented. Information on possi-ble applications for breaking up rocks of various energy sources is provided. Ideas are given on the possibility of raising the efficiency of explosives for mining rock by increasing the scale of the ex-plosive destruction. Information about the widespread adoption of these methods at Russia’s biggest iron ore companies is presented. Recent results on the fracture processes at different levels of scale up to destruction to form particles of submicron size are shown. Studying the structural transforma-tions of rock mass at the micro and macro features of allocation and distribution of energy in the charges of various designs allowed us to control the action of a new explosion by breaking up rock masses and the complex structure of multicomponent fields.
I congratulate you on our new regular meeting. Kliment Trubetskoy, co-chair of our conference, asked me to convey his warmest greetings to Prof. Vladimir Litvinenko, Rector of St. Petersburg State Mining Institute, and to all of you, participants of the conference. At present we are at the stage of reforming science and education. Our academicians and members of the Organizing Committee K.N. Trubetskoy and V.A. Chanturia are now dealing with reform issues in the RAS and therefore will not be able to participate in the conference. Our Fifth International Conference is held here, in the walls of the Mining Institute. It is the second time it is held on the basis of the Mining Institute. In 2000, the Second International Scientific Conference was held here. We still have a vivid impression of it, and therefore, when we had an opportunity to repeat the conference at your place, we took advantage of this offer with great pleasure. During the conferences we have already formed our own circle of participants and like-minded people. Here I see many of our regular participants, including foreign guests from China, Serbia, Ukraine, and other countries. This makes discussions and exchange of opinions, taking into account friendly comments and wishes, very fruitful.
The paper presents a theoretical analysis of highwall destruction by blasting. Peculiarities of blasting in high faces at open-pit mining operations in Russia are analyzed. New approaches to drilling processes in high faces are proposed. Possibilities of application of walking machines for downward digging (walking excavators) are described.
A methodology has been developed and experimental studies have been carried out to evaluate structural changes in rock samples in the near zone of explosion action. Using optical microscopy and X-ray structure analysis, it was found that the microstructure of rocks changes during the passage of shock waves: the dispersion of mineral grains increases, and the density of micro-disturbances increases by an order of magnitude.
Substantiation of the choice of the technology of rock destruction during the development of deposits by open-cut method is given, taking into account its adequacy to the properties of rocks and a set of requirements of economic, social, environmental, legal and other important aspects.
The problem of rock pre-fracture under quasi-static and di-namic loading is considered. It is shown that under dynamic loading it is possible to form pre-fracture zones of large extent. The data of ultrasonic measurements after non-destructive explosive loading are presented. Experimental data on changes in the velocities of elastic wave propagation after dynamic loading are presented.
One of the possible ways of large-scale rock mass stripping at open pits by two-stage blocks is considered. The proposed method allows 5-6 times to increase the volume of ore stripped in one blast on the block.
At the previous conference, the authors made a presentation about a very effective way of destroying materials (including rocks) with the help of low-pressure chemically active jet (CJA) impact on them. Further study of the phenomenon led to the formulation of a mathematical problem about the penetration of the CAB in the destructible material. The formulation of this problem was accompanied by consideration of the spherically symmetric thermal conductivity equation with a boundary condition of the first kind and with a threshold criterion for thermal destruction.
The problem of rock fracture is one of the most important scientific problems in the modern system of mining sciences. The efficiency of rock destruction determines the efficiency of all subsequent stages of mining production. We offer an overview of modern scientific research on rock fracture, carried out in Russia and some other CIS countries.
Long-term practice of using aquatrinitrotoluenes for blasting shows that the main drawbacks of these compositions: tendency to delamination and relatively low water resistance, have not yet been overcome. The delamination of aquatrinitrotoluene components during formation of charges in real conditions leads to reduction of specific heat of explosive transformation of the whole charge on average up to 30 % (tab.1). Currently, emulsion explosives, which do not have these drawbacks, are more widely spread in the practice of blasting works
