Articles

When the subway tunnels function, there is a need to carry out ventilation workings that ensure the circulation of fresh air at all stages of operation of the underground structure.

The authors discuss the problem of gas occurrence between (behind) casing and open gas seepage to the surface (cratering) in oil and gas wells that cause the uprise of casing pressure.

The article presents an inclined belt friction-type device for separation of bulk construction materials by particle size. The description of the device design and its operation principle are provided, and main parameters having an effect on the operation quality and performance are discussed.

The article presents innovative educational technologies for training of skilled workers and professionals for machinery manufacture companies. The description is given of the CNC mill process with the ADEM system for the manufacture of a non-standard part of sophisticated design.

The article describes the theoretical grounds of the flotation process. The main factors influencing the content of useful components in flotation products are listed. The flowsheet of the process of slurry agitation and the description of the slurry density control system equipment are also provided. A case study is described of automatic stabilizing of this characteristics under the disturbance effect caused by the instability of properties of ore slurry feed for flotation

The main objective of planning of the reproduction of underground coal mine reserves readily available for mining is the development of spatial layout concepts providing the enhancement of mineral output at minimized costs. The growth of access and development workings drivage length accompanied by the increase of their cross section results in the decline of development rates, “discontinuity of the extraction front”, and as a consequence, in losses and damages.

The article contains the analysis of overall world coal imports (including coking and steam coals) to main regions and countries in the period of 2000–2015 (2016). More detailed analysis is provided of coal imports to China. It is emphasized that coal demand in China dropped in 2015 because of the current lower rates of economic growth, outflow of investments and suspension of construction projects.

In recent years the diamond industry’s over-speculation on new consumer demand in China and India, the resulting financial consequences and pressure on the industry, fundamental shifts in generational consumer and cultural demand, and the advancement of labdiamond production technology, have made diamond industry extremely interesting to observe and challenging to predict. The future of the diamond industry hangs on the structural changes in the development of basic diamond markets. All of these forces impact all of the segments of the diamond industry, from mine to retailer

The topic examines the global gold market and the key stages in the value chain for gold from its extraction from ground through processing to its application in divers use. The analysis of the supply of gold focuses on mine production and the recycling of gold whilst the demand side analysis focuses on gold fabrication (primarily for jeweler and technology) and certain forms of investment (primarily bar and coin). The topic concentrates on those countries which are the largest producers and consumers of gold and together accounted for at least three quarters of global gold mine production and gold demand.

The article describes the main factors characterizing the advantages and shortcomings of different kinds of fuel and energy sources, provides estimates of the prospects of every fuel use with power packs of openpit mining and transport machinery. The authors propose the ways of intensive transfer to the application of natural gas motor fuels and discuss the important tasks for the successful and prompt solution of this problem. They also propose the agenda of the round-table discussion of this problem. The importance of the concentration of scientific and production efforts of the sectors concerned is emphasized.

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