US EPA

8631595 

Journal Article 

CFC issue as it affects the mining industry 

Bailey-Mcewan, M 

1991 

Chk 

Journal of the Mine Ventilation Society of South Africa
ISSN: 0368-3206 

44 

8 

118-134 

English 

The weight of evidence continues to increase that emissions of CFCs are damaging the Earth's protective ozone layer in the stratosphere. The Montreal Protocol On Substances That Deplete The Ozone Layer was revised in June 1990. As a large-scale user of refrigerating machinery employing CFC 11 and CFC 12, the mining industry must prepare for the phase-out of these refrigerants by 2000, or possibly earlier. Most existing machines using these fluids have economic lives extending well beyond 2000, and so should be converted at some stage to alternative refrigerants. A far-sighted strategy on the choice of new machines and their refrigerants must also be developed. Some alternative halocarbon refrigerants, including the well-established HCFC 22, have relatively little, but not zero, ozone-depleting potential. The revised Protocol has labelled such refrigerants transitional substances, meaning that their use is permitted for a time to aid in the phase-out of CFCs. Future revisions are likely to regulate these transitional substances and set a date beyond 2000 for their phase-out. There is no 'drop-in' alternative refrigerant for CFC 12; conversion of the 1 100 MW(R) of existing machinery employing this refrigerant will therefore be costly. The halocarbon most suitable for replacing CFC 12 appears to be HFC 134a, which has no ozone-depleting potential. It has just gone into commercial production. Newly developed halocarbon refrigerants could be regulated in future because of their suspected contribution to the 'greenhouse effect'. For new machinery, it might therefore be wise to consider ammonia and water vapour refrigeration systems wherever safe and practicable.