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where workings on a co-operative basis would probably succeed. It will be evident that there must be constant changes in the estimates of quantities of " proved " and " probably recoverable " coal as mine workings advance and new areas or mines are opened up. " Inferred " coal reserves consist of important blocks considered likely on geological grounds to contain coal, but which are unbored and too far away from known outcropsfor reliable estimates to be made.
Reserves of bituminous coal have been shown by the recent survey to be considerably smaller in the Greymouth Coalfield than was anticipated, though it is possible, but not proved, that boring may disclose the existence of some further bituminous coal in the Mount Davy area. Figures given for the Buller Coalfield are an estimate made by "officers of the MinesDepartment, with the assistance of information supplied by the New Zealand Geological Survey and the Westport Coal Co., Ltd., and are as close as can be given at present on the available data :
With the completion of the survey of the Buller Coalfield, which has now been started, a much closer estimate of coal resources for this area will be available. Recent bores in the Kawakawa district, North Auckland, have shown that there is little likelihood of further coal being available in that field, and with the practical exhaustion of the Hikurangi Coalfield only the Kamo Coalfield, which is of small extent,, remains north of Auckland. Survey of the Waikato, Waitewhena, Reefton, and Ohai areas of sub-bituminous coal is proceeding. Estimates of this class of coal are based on various geological reports, combined with information obtained during the more recent working of the seams. The figures for lignite are estimates prepared in 1927' by P. G. Morgan, late Director of the Geological Survey, less outputs to date. While there is evidence of an extensive deposit of lignite in Southland and some thick seams are being mined, it will be necessary to obtain more accurate figures by fairly close boring.
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Class of Coal. Proved recoverable. Probably recoverable. Inferred. Anthracite Bituminous (coking) Sub-bitiiminous (non-coking) Lignite (non-coking low-grade) Tons. Very little 14,160,000 139,094;000 147,000,000 Tons. Very little 56,190,000 103,992,000 377,000,000 Tons. 321,000,000 Totals 300,254,000 537,182,000 321,000,000
Bituminous Coal. Proved recoverable. Probably recoverable. Greymouth Coalfield (output, 1945, 497,982 tons) .. Buller Coalfield (output, 1945, 464,226 tons) Reeffcon Coalfield (Garvey's Creek) Tons. 8,060,000 5,100,000 1,000,000 Tons. 24,000,-000-30,190,000 2,000,000 Totals 14,160,000 56,190,000