Pneumatic conveying of ice into deep mines

Testing of a pilot installation on a gold mine has confirmed the technical feasibility of transporting ice underground by means of contiuous pneumatic pipelines, for use as a primary coolant. The pipeline length in this pilot installation is 2770 m, of which 1790 m is in a single vertical section. Both rotary valves and specially designed bottom-discharge blow vessels have been found suitable in principle for injecting the ice into the pipeline. Whereas plastic piping has been very successful in this application, the use of steel piping has not been found practicable because of the tendency of ice blockages to occur in the vertical section at any but very low flow rates. The vertical section of piping, which is vented to atmosphere at the upper end, appears to give rise to a form of standpipe flow, which in turn generates flow along a horizontal underground pipeline over substantial distances. This paper describes progress generally to date in the testing programme and includes results of performance tests for a single blow vessel in conveying ice along a horizontal pipeline. © 1987.