Abstract: A method for extracting thermal energy in an underground high temperature area of a coalfield fire area, including: determining a thermal extraction target area by a natural potential method and a ground detecting borehole; using an injection borehole to send a gaseous thermal medium to an underground high temperature area of the thermal extraction target area; after the thermal exchange between the gaseous thermal medium and a high temperature coal rock mass, the gaseous thermal medium is extracted through an extraction borehole; continuously monitoring a natural potential of the thermal extraction target area; arranging a casing-type borehole thermal exchanger in a potential anomaly region to complete the thermal exchange between the high temperature coal rocks and a liquid thermal medium; stopping the thermal extraction operations when the temperatures of the extracted gaseous thermal medium and the liquid thermal medium reach 70° C. or below.

Abstract: A method for extracting thermal energy in an underground high temperature area of a coalfield fire area, including: determining a thermal extraction target area by a natural potential method and a ground detecting borehole; using an injection borehole to send a gaseous thermal medium to an underground high temperature area of the thermal extraction target area; after the thermal exchange between the gaseous thermal medium and a high temperature coal rock mass, the gaseous thermal medium is extracted through an extraction borehole; continuously monitoring a natural potential of the thermal extraction target area; arranging a casing-type borehole thermal exchanger in a potential anomaly region to complete the thermal exchange between the high temperature coal rocks and a liquid thermal medium; stopping the thermal extraction operations when the temperatures of the extracted gaseous thermal medium and the liquid thermal medium reach 70° C. or below.

Abstract: A method of finishing glass sheets includes forming a stack comprising alternating layers of unfinished glass sheets and spacer pads. The stack is such that there is no physical contact between any two adjacent unfinished glass sheets and outer edges of the spacer pads are recessed relative to outer edges of the unfinished glass sheets. The stack is secured by clamping the unfinished glass sheets and spacer pads together and then supported on a working surface. The unfinished glass sheets of the stack are finished simultaneously while the stack is supported on the working surface. After the finishing, the stack comprises alternating layers of finished glass sheets and spacer pads.

Abstract: A method of finishing glass sheets includes forming a stack comprising alternating layers of unfinished glass sheets and spacer pads. The stack is such that there is no physical contact between any two adjacent unfinished glass sheets and outer edges of the spacer pads are recessed relative to outer edges of the unfinished glass sheets. The stack is secured by clamping the unfinished glass sheets and spacer pads together and then supported on a working surface. The unfinished glass sheets of the stack are finished simultaneously while the stack is supported on the working surface. After the finishing, the stack comprises alternating layers of finished glass sheets and spacer pads.