PRESENTATION OF CRUSHING AND GRINDING COMPLEX AS SYSTEM WITH DISTRIBUTED PARAMETERS FOR ADAPTIVE CONTROL OF ORE DRESSING PROCESSES

The article proposes representation of crushing and grinding complex in form of a system with distributed parameters of the reducing function of the processed raw materials size in order to increase the energy efficiency of entire ore preparation process. Despite the fact that many different automated control systems for domestic and foreign production technological process are now used in the ore preparation processes, there is still a need to solve the problems of optimal control of such objects in order to both reduce energy costs and improve the quality of the final product. In terms of energy consumption, grinding processes are superior to crushing processes, so it is necessary to consider the crushing and grinding complex as a whole to increase the whole process energy efficiency. Since the processes of crushing, grinding and classification are purely random and at any time are characterized by transient probabilities, and the crushing and grinding complex occupies a large area and is geographically distributed in space, it should be considered as a system with distributed parameters of raw material size reduction, recyclable. Redistribution of loads between the individual components of this complex in accordance with the current characteristics of processed ore and the state of process equipment allows to reduce the load on the final stage - it is grinding, which in turn contributes to the overall reduction of energy consumption. The peculiarity of this approach is the need for the formation of spatial-temporal controls on basis of spatially distributed control of the object, the use of appropriate feedback signals and regulators with spatially distributed control effects.

Designs of new operating copper processing plants: process types, equipment selection, industry trends

The article describes the largest operating processing plants for lowgrade copper sulphide ores of our time: 10 plants using the semi-autogenous grinding (SAG) technology and 10 plants using high-pressure grinding rolls (HPGR), with the output of 18 to 100 Mtpa. The unfavorable natural and economic factors are balanced by improved ore preparation and concentration technologies and high-capacity equipment units, combined with cost-saving layout solutions. The ore preparation sector is currently divided between the competing technologies of semi-autogenous grinding and HPGR. The article contains an overview of their advantages and disadvantages. The world’s largest monosection with the capacity of 55.5 Mtpa, that uses the SAG technology, is described. The role of the Drop Weght Test JKSimMet (A×b) parameter in the selection of the ore preparation method and the trend for using HPGR in the processing of strong ores are shown. Examples are provided for the consequences of an inadequate assessment of the feed strength in SAG-based plant designs. Examples of ore preparation process intensification through the use of HPGR in semi-autogenous grinding circuits are also given. The volume of impeller flotation cells installed has reached 600 m3. An overview of the two largest processing plants of our time with the output of 88 and 100 Mtpa of ore is presented. The innovative technical solutions of a newest low-capacity copper plant are highlighted. Based on the results of the overview, a future processing plant is predicted to use ∅12.8–13 m SAG mills, HPGRs with the roll diameter of 3 m, vertical VTM-7000 mills in ore grinding cycles, large fine screens, large-scale impeller flotation cells, and staged SFR and DFR flotation reactors.

PROBLEMS OF ORE PREPARATION FOR HEAP LEACHING

The issues of reagent leaching of metals in stacks in a historical cut are considered. It is shown that more than 1/3 of the chipped ore in size does not meet the conditions for extract-ing metals from it and requires regrinding. The features of mills are considered and the ad-vantages of grinding in a high-speed mill - disintegrator are determined. The information on innovations in the optimization of grinding equipment, which can reduce the cost of production by 10…15 %, is given.

Methodological Framework for Experiments Related to Bloomery Iron Production Procedures: Ore Preparation and Smelting

Systematic, well-designed experimental research and standardized documentation is a starting point for explaining the outcome of experiments and comparative analyses, whether within single experimental research or a wider frame of comparison with other research. This contribution presents a sequence of research procedures that served as a basis for the design and implementation of experiments related to bloomery iron production procedures. A proposal for the method of documentation is made with the aim of combining all general functional parameters relevant to the procedures of ore preparation and direct process of reduction in the reconstruction of a smelting furnace, based on personal experiences and the current state of experimental research related to iron production. The objective is to give a structured basic template of main parameters that should be recorded and reported when performing experiments related to the mentioned procedures. The hope is to bring forward a layout that should be upgraded and further developed based on specific research questions one could have.

Optimization of the drilling-and-blasting process to improve fragmentation by creating of a preliminary stress in a block

At mining and processing complexes, many parameters today are evaluated from the point of view of the total process from geology to the final product. Changes in certain mining parameters inevitable lead to the changes in the following downstream processes. In this article, the focus is on the ore fragmentation, which is one of the most important parameters in many mines as it affects the downstream ore preparation and processing efficiencies, productivities and costs. In most of the cases, the cheapest way to improve the fragmentation of the ore is by changing the drilling-and-blasting design parameters. It of course increases the mining costs, but at the same time decreases the costs of the following processes, which are normally significantly higher. Therefore, authors of this article propose a new way of optimization of the drilling-and-blasting process by introducing new blast design modifications. Based on the analysis, research of the scientific information and the mining practise, the authors discuss the way of creation of the preliminary stress in the block of the open pit and hence improving fragmentation. Physical experimental blasts in “Belaya Gorka” open pit were performed and shown positive results reflecting a potential for continuation of the research in this direction in the future.

Mining-geological and physico-chemical indicators determining the success of the use of block underground and heap leaching

The success of the physico-chemical technologies’ application in the development of ore deposits, such as underground and heap leaching, depends on the petrographic and mineral composition of the ores and their host rocks, type of reagents leaching the useful component, technology of ore preparation and irrigation modes of lumpy ores. The efficiency of leaching of uranium-ore minerals is determined by the physico-chemical laws of the interaction of reagents with the ore material. In the course of the research, the relationship between the silica content in the rocks containing mineralization and their physical and mechanical properties was established. This makes it possible, knowing the type of rocks, to predict the conditions of ore preparation by drilling and blasting to obtain the optimal piece size for leaching. In addition, the influence of the ore texture on the leaching efficiency was proved experimentally. Previous researchers found that the rate of conversion of uranium to the mobile state during leaching depends on the rate of penetration of the leaching reagent into the piece, displayed by the effective diffusion coefficient (Kef). The analysis of mining and geological information made it possible to establish the relationship between the Kef and the type of host rocks through the SiO2 content and the type of uranium minerals through the uranium content. The obtained knowledge makes it possible to predict favorable conditions for the use of physico-chemical geotechnologies in the development of rock-poor uranium deposits

Studi Ekstraksi Bijih Emas Asal Pesawaran dengan Metode Pelindian Agitasi dalam Larutan Sianida

Research on the extraction of gold ore from Pesawaran, , Lampung, Indonesia, was carried out using the agitation leaching method in cyanide solution. This study aimed to obtain information on the use of conventional cyanidation methods for extracting gold from the Pesawaran gold ore. The ore preparation was carried out in the form of crushing, grinding and sieving to obtain samples with fraction sizes of -60 + 100 mesh, -100 +150 mesh, -150 + 200 mesh and -200 mesh. The ore characterization was performed using XRD, XRF, SEM-EDX, and wet chemical analysis. The XRD analysis showed that the main mineral phases were silica, hematite, aluminium hydroxide and orthoclase. The major constituents of the ore were Si (53,628%), Fe (15,996%), K (19,744%) and Al (8,045%). The Au content was determined by wet chemical analysis and was found to be 9.67 ppm. The experimental results show that the highest percentage of gold extraction of 83.33% was obtained using sodium cyanide at a concentration of 1000 ppm, a percent solids of 40% and a grain size of 200 mesh. Higher gold extraction was not achieved despite the use of a high cyanide concentration was probably because the remaining gold was not properly liberated. The results of SEM-EDX analysis showed that the gold grain size was <20 µm, while the grinding was performed only to a sieve size of -200 mesh (74 µm).

Optimization of parameters of open-pit screening and dumping stations

Introduction. The mining and geological features of a number of deposits lead to the fact that during the development of the massif under the influence of drilling and blasting operations, the degree of crushing of a mineral depends on the content of useful components in it, and the chemical composition of the ore is differentiated by size classes. The determined relationship between the quality of the ore mass and its size can be used to increase the efficiency of the ore preparation technology through the use of screening and dumping stations (SDS) in open pits. The implementation of the ore preparation technology based on the SDS will allow to reduce the costs of enrichment and transportation of the ore mass by separating its substandard part directly in the open pit and excluding it from the traffic flow at the processing plant, where the efficient operation of SDS is possible by optimizing a number of parameters as mining transport equipment serving SDS and a screener itself. Results. To determine the main parameters of SDS the characteristics of the initial movement of the rock mass along the inclined surface of the screen were determined, such as the productivity of unloading the vehicle onto the surface, the initial thickness of the layer for feeding and the speed of movement of the rock mass along the slope of the screener. Based on the presented algorithm, the main characteristics of the screening process are calculated: the size of the material flow layer in the i-th screener section; the speed of movement of the bulk mass along the screener; the average size of a piece in the starting material and the output of the material into screen throughs. The parameters of the screening process were determined on the basis of a given relative content of the size class of the material supplied to the surface of the screener, subject to its uniform distribution within the class. The optimized parameters of SDS were selected: the angle of inclination of the screener and the linear dimensions of the unloading platform, depending on the dimensions of the dump truck. Determination of the optimal parameters of SDS was carried out by constructing a generalized desirability function for two optimized criteria: the material yield to screen throughs and the oversize of the screener. Based on results of the calculation, optimization graphs of the dependence of the optimization function on the angle of inclination of the surface of the screener and the carrying capacity of the dump truck unloaded onto the screener were constructed. Conclusions. The optimal angle of inclination of SDS screen is 40° –42° and does not depend on the grain size distribution of the feedstock supplied to screening.