Mining enterprises are widely introducing digital technologies and automation is one of such tools. Granularity monitoring, namely, the size determination of rock mass pieces is a common operational component of the processes that extract minerals by open-pit mining. The article proposes an approach that, in addition to the lump size distribution, makes it possible to estimate the lump form distribution as well. To investigate the effectiveness of monitoring the form of blasted rock mass lumps, the authors conducted experiments in four stages related to the rock condition. They include geological occurrence, explosive crushing, trommelling, and mill crushing. The relationship between these stages is presented and the change in the lumps fragment form is traced. The present article proposes an informational and analytical model of the processes at mining enterprises, extracting minerals by open-pit mining, as well as an algorithm for determining the lumps form and obtaining their distribution in the rock mass.

A review of the existing optoelectron monitoring devices revealed that the design of optoelectron detectors of the mine atmosphere does not sufficiently take into account the factor of external optical interference. This includes any extraneous source of thermal emission: a source of artificial lighting or enterprises. As a consequence, the optoelectron detectors -based safety systems currently installed at mining sites are not able to ensure properly the detection of the ignition source in the presence of optical interference. Thus, it is necessary to determine the working spectral wavelength ranges from methane and coal dust explosions. The article presents the results of experimental research devoted to the methane-air mixture and coal dust explosion spectral analysis by means of the photoelectric method. The ignition of a methane-air mixture of stoichiometric concentration (9.5%) and coal dust of size characterized by the dispersion of 63–94 microns and concentration of 200 g/m³ was carried out in a 20 L spherical chamber with an initial temperature in the setup of 18–22 °C at atmospheric pressure. Then, photometry of the explosion light flux was conducted on a photoelectric unit. Operating spectral wavelength ranges from methane and coal dust explosions were determined. For the methane-air mixture, it is advisable to use the spectral regions at the maximum emission of 390 and 900 nm. The spectrum section at the maximum emission of 620 nm was sufficient for dust-air mixture. It enabled us to select the wavelength ranges for automatic explosion suppression systems’ launching references. This will exclude false triggering of the explosion suppression system from other radiation sources. The research results will help to improve the decision-making credibility of the device in its direct design. The results will be used in further research to design noise-resistant optical flame detection sensors with a high response rate.

Моделирование режима протекания процесса сварки плоских листовых деталей взрывом

The problem to ensure the safety of objects which are in the area of blasting operations, ensuring the destruction of hard rocks, remains relevant. The article presents the results of a large-scale experiment to determine the safe conditions for conducting drilling and blasting operations near the active gas pipeline. The simplest and most reliable way to ensure the safety of the protected object from seismic impact is to reduce the intensity of the seismic wave, which is achieved by changing the parameters of drilling and blasting operations. This requires research to determine the impact of blasting operations on the parameters of seismic waves and the development of methods for measuring these parameters. The paper presents a detailed analysis of the seismic blast wave impact on the displacement of the ground and the model gas pipeline. The features of seismic monitoring during blasting operations near the active gas pipeline are shown. The seismic coefficients and attenuation coefficient of seismic waves are determined. It is proved that the readings of the seismic receivers on the surface and in the depth of the massive differ by two or more times. Проблема обеспечения безопасности объектов, которые попадают в зону ведения взрывных работ, обеспечивающих разрушение крепких горных пород, остается актуальной. В статье приводятся результаты крупномасштабного эксперимента по определению безопасных условий ведения буровзрывных работ вблизи действующего газопровода. Наиболее простым и надежным способом обеспечения безопасности охраняемого объекта от сейсмического воздействия является уменьшение интенсивности сейсмовзрывной волны, что достигается путем изменения параметров буровзрывных работ. Для этого необходимы исследования по определению влияния взрывных работ на параметры сейсмовзрывных волн и разработка методик измерения этих параметров. В работе выполнен детальный анализ влияния сейсмовзрывной волны на смещения грунта и модельного газопровода. Показаны особенности проведения сейсмического мониторинга при ведении взрывных работ рядом с действующим газопроводом. Определены коэффициенты сейсмичности и затухания сейсмовзрывных волн. Доказано, что показания сейсмоприемников на поверхности и в глубине массива отличаются в два и более раз.

This article is dedicated to the problem of realistic colour rendering of space object images using the tools of computer graphics. In the form of a short essay, the authors describe the essence, sources and functionality of modern graphics applications. Particular attention is paid to the application of modern graphics in space science. The specific purpose of the study is the use of computer graphics in the field of remote sensing of the Earth’s surface. This article describes a method for synthesizing images to develop realistic 3D models of colour Earth images in the visible spectral range, observed from geostationary orbits. The method is based on the improved model of atmospheric radiation for arbitrary sighting conditions in an inhomogeneous spherical atmosphere. Physical models of horizontally inhomogeneous distributions of atmospheric density, temperature and albedo of the Earth were improved. All calculations were performed in accordance with the model of molecular scattering of radiation in a spherical atmosphere, taking into account sunlight forward-scattering and reflection from the planet’s surface. This allows us to obtain images of the Earth in its various phases, observed from arbitrary heights. The obtained theoretical colour images of the Earth were compared with black and white images from modern geostationary satellites.

At many quarries for the extraction of building stone there is a problem of increased output of fines after all stages of crushing and grinding, which leads to a decrease in the economic performance of mining enterprises. The fine fraction is formed by the crushing / grinding of prefractured rock mass. Reducing the intensity and size of the prefracture zones will lead to a solution to the problem at hand. To determine the effect of explosive detonation properties on the degree of structural weakening of a rock mass, studies were conducted to measure the detonation velocity, stresses generated by a blast in the rock mass, as well as laboratory studies of microfracturing by X-ray computer microtomography. The size of the prefracture zones increases from 33 to 77 charge radii with increasing the detonation velocity from 2 to 5.2 km/s. The dependence of the number of microdefects (microfractures) generated by a blast on the velocity of explosive detonation takes the formof an exponent for the near zone and is linear for the distances far from the blast. According to the data of the experiments conducted at short distances (10R), the density of induced microfracturing N is within ≈5 thousand pcs/cm3, and with increasing the detonation velocity it increases to ≈13.8 thousand pcs/cm3. At medium (40R) and long (70R) distances, N increases from ≈750 to ≈2,400 pcs/cm3 and from 0 to ≈200 pcs/cm3, respectively. Using explosives with a reduced detonation velocity allows reducing the “surplus” impact on a rock mass and thus reducing the intensity of prefracture in the zone of controlled crushing during a blast. The study allowed obtaining quantitative parameters of the intensity and size of the prefracture zones, which compose the supplement to findings of historical studies on qualitative determination of prefracture.