Kentor Gold has lodged prospecting licence applications for five areas in the Kyrgyz Republic considered to be prospective for geothermal energy of the hot fractured rock type analogous to the Cooper Basin. The exploration target in each area is hot fractured granite with temperatures in excess of 250°C. Should the exploration programme be successful, the business plan is to generate emission-free electricity for export to China. The rapidly developing Xinjiang-Uyghur Autonomous Region of China lies adjacent to the Kyrgyz Republic.
Kentor’s applications are the first for geothermal energy in the Kyrgyz Republic. While Kentor has received verbal assurance from the Kyrgyz State Agency for Geology and Mineral Resources that the applications will be favourably considered, the company is awaiting confirmation in writing.
North Issykkul and South Issykkul PLA’s Lake Issykkul is a large (22,080 km2) body of water at an altitude of 1,600 m in the Tien Shan Mountains, which remains unfrozen even throughout severe winters. The depth of the lake is 668 m. Soviet and Russian research indicates that the thermal energy to warm the lake enters through a broad system of trans-orogenic faults striking north-west across the middle of the lake, and that the heat enters from the sides rather than the bottom.
On the northern shore, basement granites lie under 1-2 km of sedimentary material. Data collected in petroleum exploration wells and groundwater wells showed geothermal gradients ranging from zero near surface to a maximum of 88°C/km at deeper levels. The area of the lake shore where the highest temperatures are coincident with significant sedimentary cover has been incorporated into the application for North Issykkul, 159 km2 around the resort town of Cholpon Ata.
On the southern shore, the sedimentary cover is thicker. Seismic surveys indicate a depth of cover of up to 5 km. There has been no deep drilling in this area of the southern shore, but drilling for groundwater has produced water at elevated temperatures. This section of the southern shore, centred on Barskaun, has been incorporated into the application for South Issykkul, 248 km2.
The Kyzylompul area is characterized by syenite and granosyenite intrusions forming the Kyzylompul and Sandyk massifs. These massifs contain anomalous concentrations of radioactive material including uranium, thorium, and potassium. Natural radioactivity levels recorded by Soviet investigators are up to 120 μR/h (micro-Roentgen per hour). Normal natural background levels of radiation range from 0.17 to 11 μR/h.
The radioactive granites outcrop in some areas, where heat is dissipated. However, large areas are under significant depths of sedimentary cover. The exploration target is radioactive granite where it lies under an insulating cover of about 3 km and the temperature has thus built up to around 250°C. The Kyzylompul licence application covers 1,657 km2.
The Aksai Basin is underlain by young granites of the same age as the Kyzylompul massif, and there is sedimentary cover of up to 5 km. Anomalously high heat flows have been recorded by Soviet researchers, and Soviet reports record geothermal waters rising on a number of faults in the basin. A substantial amount of geophysical work has been completed over the Aksai Basin, including gravity, electrical sounding and aeromagnetic surveys. Kentor now has access to the records of this work. An area of 3,455 km2 incorporating where heat anomalies have been recorded has been applied for.
While exploring for tin, Soviet geologists developed an adit which passed through a fault into hot granite 700 m from the portal. Rock temperatures of over 70°C persisted until the adit was abandoned 1,000 m further on. The implied geothermal gradient is 150°C/km. It is thought that these elevated temperatures are associated with the intersection of a north-south striking fault with the Inylchek suture line. An area of interest covering 22 km2 has been applied for.
Kentor is undertaking an aggressive gold exploration programme around the Centerra-owned Kumtor gold mine together with an active and successful project generation programme elsewhere in the Kyrgyz Republic.