The conception of developing unallocated fund of subsoil raw material resources base in the coal mining industry

Coal mining industry raw material bases analysis of allocated, newly introduced and unsold subsoil reserve fund demonstrates a fast depletion of the reserves with favorable geological factors of mining which meet the requirements of traditional mining technologies. In the coming years meeting the demand on certain technological coal ranks (K, KZh, KC, KCN, KO, OC, TC, CC) cannot be provided without exploiting coal deposit sites that contain hard to recover reserves and without developing and implementing new mining technologies oriented on complex mining and geological conditions. It requires a special program for fulfilling scientific researches on the development of methodological approaches, technical and technological solutions and testing new technologies for hard to recover coal reserves which can provide rational subsurface resources utilization and protection.


Introduction
Coal mining sector of Russia has significant reserves of different technological ranks of coal. Predicted coal resources in Russia are estimated as 1528.9 billion tonnes of Р1+Р2+Р3 categories (where Р1 category is 468.1 billion tonnes), balance reserves of А+В+С1+С2 categories are estimated at the quantity of 275.0 billion tonnes (where С2 category is 78.9 billion tonnes) [1,2], so it makes about 15 percent of all global reserves [3]. Over half balance reserves of coal goes to brown coal, it is about 5.1 percent, 43.6 percent goes to bituminous coal (where 41.2 percent is coking coal, it is 49.5 billion tonnes) and 3.3 percent is anthracite coal [1].
Reserves allocation on the territory of Russia is rather uneven as about 73 percent of balance reserves and 80,6 percent of predicted coal reserves go to Kansko-Achinskey and Kuznetsk basins while the share of other 20 basins do not exceed 17 percent (table.1) [4].
A major part of the explored reserves accounted by the State balance was estimated during the Soviet period and only by the conditional parameters of thickness and ash-content of the coal seams. The reality of those times, when this sector was under the condition of allocating investment support, allowed utilizing mining technologies with low level of production efficiency: that is mining coal seams with high tectonic faulting (with the faulting indicator up to 250 m/ha) with the whole range of seam inclinations, with high level of gas-bearing capacity and other complicating mining and geological factors. At present, coalmining enterprises are focused on the reserves, which mining and geological mode of occurrence can provide the implementation of high performance mining technologies. In underground mining, the longwall mining system with coal faces equipped with highly productive mechanized complexes is basically used. Their effective activity provides high stable load on the coal faces (over 6-8 thousand tonnes per day) which is possible only under the favorable mining-geological conditions [5]. The admissible faulty level of the mining fields decreased to 30-50 m/ha (depending on the value of the extracted coal). Longstanding years of selective involvement into the mining only of the areas with favorable (applicable only to the existing mining technologies) mining-geological conditions resulted in the significant decrease of mineral raw material base of the mining sector and first of all in the areas with the developed infrastructure.   The development of large El'ginskey coking coal deposit in Yuzhno-Yakutskey coal basin influenced positively on supplying the sector with technological ranks of highly valued caking coal such as fat coal (Zh) and gas-fat coal (GZh). The share of these coals in reserves increased to 25.1 percent (figure1) and in extracting coking coal it increased to 53.8 percent. This created production potential allows increasing the volume of extracting El'ginskey coal nearly in two times by the opencast method.
The share of highly-valued coke-forming group of coals such as coking fat coal (KZh), coking coal (K), coking lean coal (KO) is insignificant as in commercial reserves of bituminous coals (5.2 percent) so as in extraction (5.4 percent). The share of technological coal ranks such as coking caking coal (KC), low-caking low-metamorphosed coal (KCN), lean caking coal (OC) used as a component of the coke charge in commercial reserves of bituminous coals is 5.3 percent and 7.6 percent in extraction.
The share of anthracites in commercial reserves is 2.9 percent and 6.5 percent in extraction. About 65.1 percent of all commercial reserves are meant for open casting, however, 38.9 percent of the reserves are represented by less valued long-flame coals (D) [5]. Over half of commercial reserves of highly valued coking coals are meant for underground mining. Thus, constant deterioration of mining-geological conditions in underground mining, when the medium depth of extraction prevails over 482.5 meters, makes 90.8 percent of all developed coal seams dangerous at least on one of danger factors [1].
Thus, raw material base of the coal mining enterprise operative fund demonstrates high intensity of medium-, high-metamorphosed coal reserves mining starting from coking coal (K) and finishing with anthracite coal (A). Disbalance between the volume of the reserves and the volume of the extraction predetermines the changes in the existing coal market structure whereby the reserves and extraction of such coal ranks as low-caking low-metamorphosed coal (KCN), coking caking coal (KC), lean caking coal (OC), lean low caking coal (TC) and the major share of coking lean coal (KO) is produced only in Kuznetsk coal basin [6,7].

Newly introduced underground mining and opencast fund
For the purpose of developing operating and newly constructed mining enterprises (according to the data of the competitive tenders and auctions of 2008-2019) in Kuzbass the subsurface resources sites with total reserves and prognostic resources of 10.4 billion tonnes were delivered in possession.
In gross reserves additions of mineral raw material resource base the share of low-metamorphosed power-generating (steam) coals of D, DG, G ranks made 54 percent, coking coal made 31 percent, high-metamorphosed power-generating coals of CC, TC, T ranks and anthracites made 15 percent. In the structure of subsurface sites meant for new mine constructions these shares made 58 percent, 23 percent and 19 percent respectively and in the additional cuttings of spare lands of the acting coal enterprises it made 50 percent, 12 percent and 38 percent respectively (figure 2) [8]. The volume of the reserves and the predicted coal reserves on the subsurface sites meant for underground mining is insignificantly (on 2 percent) low than the volume meant for open-casting. The reserves and the resources on the sites of new mine construction is about one third of the total volume for mineral-raw material base growth and are (72 percent) meant for constructing open-casts. At the same time, total explored raw materials potential of the basin for opencast method is four times less than the one for underground mining. It shows the resource disproportion in technological deployment of the basin that in the further will result negatively on social and ecological situation of industrially developed and densely populated region.  The grade composition of the coking coal reserves and resources is represented basically by fat (Zh) and gas-fat (GZh) coals, in lesser degree it is represented by coking (K) and coking fat (KZh) coals and in very insignificant degree it is represented by coking low-caking low-metamorphosed (KCN), coking lean (KO), lean (T) and low caking (CC) coals. Thus 55 percent of subsurface sites are referred to the second and the third groups of complexity and are subject only to opencast development.

Unallocated subsoil reserve fund
Unallocated subsoil reserve fund is a raw material reserve and mining geological and mining technological conditions of its exploitation define the perspective of coal mining industry technical and technological development policy.
The major part of all explored bituminous coal reserves (49 billion tonnes) of all ranks is concentrated in Kuznetsk coal basin. Mining and geological factors of coal seam occurrence of the Basin are characterized by a wide variety.
The analysis of unallocated subsoil reserve fund of Kuznetsk Basin revealed that more than half of the fund is represented by sites of the second and the third groups of geological structure complexity and basically containing coking and highly-demanded high-metamorphosed power-generating coals ( figure 4). However, only 21 percent of all the reserves of the fund can be developed by opencast method and the share of highly demanded by the industry reserves of some coal ranks (GZh, Zh, KZh, K, KC, OC, CC) do not exceed 5 percent (figure 5).

Conclusion
Russian coal deposits raw material base according to its grade composition do not procure its replenishment by the technological ranks of K, KZh, KC, KCN, KO, OC, TC, CC coal in the nearest future as their explored reserves are concentrated mainly in Kuznetsk basin in the subsurface sites of the second and the third complexity groups and cannot be developed by the opencast method. Maintaining the achieved volumes and supplying the demand on some technological ranks of coal such as K, KZh, KC, TC, KCN, KO, OC, CC is impossible without developing and applying new modern mining technologies (underground mining first of all) which provide effective and safe mining of the deposits with complex mining-geological and mining-technological conditions [9][10].
Considering the acting amendment to the Law of the Russian Federation "About Subsoil" devoted to introduction of a new type of subsurface reserves utilization which is aimed at "developing technologies for geological studying, exploring and mining hard-to-recover mineral resources reserves" it is offered to refer such technological coal ranks reserves as K, KZh, KC, KCH, KO, OC, TC, CC at the subsurface sites with complex mining and geological conditions the mining of which applying commercial mining technologies is impossible or ineffective to hard-to-recover mineral resources.
The strategic program for conducting scientific researches directed on the development of the methodological approaches, technical and technological solutions, testing new technologies for hardto-recover coal reserves exploitation, which will provide rational utilization and protection of subsurface resources is of the great need at present.
To motivate mineral resource developers for mining such subsurface sites it is supposed to waive them from recurring payments for subsurface sites usage and royalty [1] and to make provisions for introducing other preferential advantages.
Implementing the conception of coal deposits unallocated subsoil reserve fund exploitation in the nearest future will satisfy the demand on technological coal ranks, the expected deficit of which is demonstrated by the state of the coal mining industry mineral raw material resource base.