The paper presents economic justification for applicability of near-surface geothermal installations in Luga region, based on results of techno-economic calculations as well as integrated technical and economic comparison of different prediction scenarios of heat supply, both conventional and using geothermal heat pumps (GHP). Construction costs of a near-surface geothermal system can exceed the costs of central heating by 50-100 %. However, operation and maintenance (O&M) costs of heat production for geothermal systems are 50-70 % lower than for conventional sources of heating. Currently this technology is very important, it is applied in various countries (USA, Germany, Japan, China etc.), and depending on the region both near-surface and deep boreholes are being used. World practice of near-surface geothermal systems application is reviewed in the paper.
One of the main negative features of the group of chamber-and-pillar systems of development are high losses of ore in the left pillars, with increasing depth of mining works the size of pillars increases, and ore losses increase accordingly, reaching 40-60%. Thus, the variants of chamber-and-pillar mining system used at small and medium depths with plunging of mining works to great depths become technically and economically ineffective. Multistage variants of this development system, in particular with excavation of chambers of the first stage and their subsequent backfilling, received experimental and industrial application, including at SUBR. In connection with the increase in the depth of mining operations, an important task in conditions of SUBR is to determine the limits of economic efficiency and further application of classical variants of the chamber-and-pillar system and transition to variants with multistage excavation. In order to design the mining of new, deeper horizons, it is necessary to optimize the parameters of applying the variants of the development system. According to the developed economic-mathematical model the program of ore mining cost calculation was made, the results of calculations of the program were transferred to the electronic tables EXEL, where the effective limits of different variants of chamber-and-pillar system of development were received.
