On determining the parameters of face blocks during mining operations with backhoes

The backhoe hydraulic shovels (backhoes) have been widely used in open-pit mining operations in the Kuznetsk coal basin since the early 2000s. Now their number is growing every year, both because new operations begin on new sites, and because of the backhoe advantages. However, up to now parameters of their operation, more particularly the parameters of the face blocks, are often taken according to the actual data, i.e. based on the accumulated experience of the mining companies, and are not calculated using the approved scientifically validated methods. In the given article the authors give some preconditions for creation of a uniform methodology to calculate parameters of the face blocks depending on mining-geological and miningtechnical conditions. It is noted that the manufacturers of excavation equipment quote the data corresponding to the maximum possible parameters of the equipment operation, in particular the height of the excavated layer, as a result of which it is rather difficult to apply this in practice. Preliminary conclusions about the need to take into account the diversity of the above conditions and their interrelation with the parameters of a particular model of the excavation and loading equipment have been made.

Permeability of Coking Coals and Patterns of Its Change in Leninsky Area, Kuznetsk Coal Basin, Russia

A prediction of the permeability of gas-bearing coking coals in the Leninsky area, Kuznetsk coal basin (Kuzbass), which is promising for the production of coal methane, was performed. The results of laboratory studies of coal permeability and cleat compressibility under hydrostatic stress conditions are presented. As the confining pressure increased by 8 times (from 1 MPa to 8 MPa), the coal permeability perpendicular to the butt cleat direction decreased by 6.7 times (from 60 mD to 9 mD). The coal cleat compressibility was 0.085 MPa−1. On the basis of the results of filtration tests and microstructural analysis of the coking coals, we provide the estimation of the permeability anisotropy along the bedding planes (perpendicular to the face and butt cleat directions). The predicted dependences of gas-bearing coking coal permeability perpendicular to the butt and face cleat directions on depth and on features of coal seam bedding were determined under uniaxial strain conditions. It was found that in the coking coal depth intervals, as the depth increased, their permeability decreased by 61–82%. The obtained results can be used to select facilities and to design industrial works for the extraction of coal methane in the region.

Determination of total and fine airborne dust in coals

Issues on evaluation of coals ability to liberate airborne dust during transportation and transloading are nowadays relevantly current. In the current work, a new method was presented for evaluation of dust contents in coals. It is based on modeling of the processes of coals transloading and transportation. The essence is to stir coals sample of size <3mm at a constant rotation rate with a simultaneous passing a fixed volume of air through a filter system and determining the total airborne dust content and dust class sizes more or less than 10 microns. During the tests, a sample of commodity coal is used as a residue of a sieve analysis of the representative coal sample after the sieve of 3 mm. Experiments were held at two hard coals of the Kuznetsk coal basin differing in their metamorphism degree and petrographic composition. It was established that within the measurement error, the total amount of airborne dust able to be released during transloading for both the considered samples is comparable. On the other hand, the size classes distribution for dust particles over or less than 10 microns varies significantly and depends on the coals rank and petrographic composition. High inertinite contents determines, presumably, the increase of fine dust particles (less than 10 microns) in the total airborne dust released.

Hydrogeological conditions of potable water supply the Kuznetsk Coal Basin, Russia

The article deals with hydrogeological conditions of the groundwater resources in the western part of the Kuznetsk depression, a coal and ore mining region. On the basis of a scheme of hydrogeological boundary conditions, a numerical geologic filtration model is developed for calculation of groundwater resources in the study area. The hydrologic budget of the numerical model is evaluated for assessment of infiltration recharge of groundwater resources.