Nanostructures of coal beds in the Sherubaynurinsky section of the Karaganda basin

Abstract

Purpose. To determine the thickness of thin films of coal matter in the Sherubaynurinsky area of the Karaganda basin and their effect on the physical properties of these films. Methodology. In order to calculate the thickness of the surface layer of the coal substance using our proposed formula, one needs to know the molar mass and density. We will use the well-known work where it is shown that such a characteristic as the molecular weight of coal reflects rather well the degree of metamorphism, and is also decisive for the study on the composition and structure of coal raw materials. Findings. The role of the thickness of the surface layer of coal in the course of most physical processes is shown. A thin layer of coal matter differs significantly from metals and other compounds. But it is close to the structure of higher fullerenes. One fundamental parameter, the atomic volume of the surface layer, determines all the properties of the nanostructure of this layer. Originality. For the first time, the thickness of the surface layer of the coal substance has been determined, which is two orders of magnitude greater than the thickness of pure metals. The thickness of the surface layer of higher fullerenes C96 (135 nm) is close to that for OC coal (146 nm). The average statistical structural unit of coal corresponds to higher fullerenes with the number of carbon atoms in the cluster >100, which is a unique feature of coal matter. The thickness of the surface layer of coal in the Sherubaynurinsky area of the Karaganda basin with a size of ~150200 nm was obtained. This structure is a nanostructure. In this layer, the physicochemical properties of nanomaterials occur: a change in the crystalline (supramolecular) structure of coal; a change in its electronic structure and its electrical conductivity; change in the conditions of the stress state of coal; change in the conditions of methane diffusion in coal seams and many other phenomena. Practical value. The natural gas content C0 depends linearly on the reciprocal of d(I). For coal seam k, where d(I) = 180.8 nm, it was obtained 0 = 19 m3/t. After the release of coal and gas, the average value of C0 = 216 m3/t at a seam depth of 430 m, and in the Sherubaynurinsky area C0 = 14 m3/t at an average thickness of the surface layer d(I) = 170 nm. Hence, after the explosion d(I)v = 35 nm, i.e. the layer thickness decreases by almost 5 times, leading to the formation of coal dust. We have considered only a part of the nanostructure issues: porosity and gas content, explosiveness and moisture content of coal seams, and have shown that all physical phenomena in a thin layer of coal have a dimensional dependence and determine structures unexplored until now, and phenomena studies on which are necessary for the practice of mining.

Assessment of the influence of the surface layer of coals on gas-dynamic phenomena in the coal seam

“…Let us calculate the thickness of the nanolayer of higher fullerenes. Thus, for fullerene C 96 = R(I) = 135 nm, which is close to anthracite (Table 1) [13,14]. From Table 1, the thick ness of the surface layer of coals is within the range of R(I) ≈ ≈ 0.2-0.15 microns.…”

“…Areas of coal seams containing highly dispersed coal (nanoparticles) are areas of unstable methane state, where there is a transition of methane from the bound state to the free state at unloading of the seam and temperature increase in this zone, this leads to a sharp increase in the activation energy of methanebearing coal decay. In [13] this energy is defined by the expression…”

Mathematical model of the formation of barite-lead mineralization of the Ushkatyn III deposit (Central Kazakhstan)

“…It is known [24] that the sizes of geomaterials and elements blocks of the earth's crust are not arbitrary but make a certain discrete series in which the ratio of the block sizes of the n-th order to the size of neighboring blocks of the order (n+1) and (n-1) satisfies some fundamental ratio: the universal principle of material divisibility during destruction:…”

“…The limestone surface layer thickness that mainly consists of CaO (Table 2), is 16.64 nm, which relates this layer to a nanostructure [24].…”