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lieries. Nearly all of those must be visited, and at each the 
quantity of coal remaining must be determined. A very large 
number of the coal proprietors would offer no objection to this; 
they would, indeed, render every possible assistance. But 
there are many who would very strongly object to this inqui- 
sition. Few men, indeed, would like it to be published that 
they had but two or three years' supply of coal left in their 
mines. This, however, is a difficulty which may be overcome 
by judicious management. Although there would be very 
sufficient reasons for refusing to furnish the information from 
individual collieries, there could be none if the collieries were 
taken in groups. In most cases, the coal trade associations 
would undertake to furnish the required data, respecting all the 
collieries within their jurisdiction. 
Having stated the difficulties, and expressed my opinion that 
there are none which could not be overcome, it only remains 
for me to show, that no reliance can be placed, upon any state- 
ment which has hitherto been published. Instead of making 
the inquiry in the way indicated, which is the only method by 
which we can arrive at anything approaching to correctness, 
we find the estimates made after this manner. 
Estimate of the Mineral Resources of the South Wales Goal 
Basin. 
1. Superficial area 906 square miles. 
2. Greatest thickness of Coal Measures with coal 10,000 feet. 
3. Number of coal-seams from 2 feet and 
upwards, 25 giving a thickness of 84 feet of workable coal. 
4. Total quantity of coal (corrected for denu- 
dation) 48,000 millions of tons. 
5. Deduct one-half for quantity below 4,000 
feet, leaving 24,000 millions of tons. 
6. Deduct one-third for waste, and quantity 
already extracted, leaving for future supply 16,000 millions of tons. 
7. Divide this by 8 millions of tons, the average annual produce, we find 
that the supply will last at the present rate of consumption 2,000 years. 
Now, Mr. F. Foster, in his communication to the Natural 
History Society of Newcastle, gives an area to the South 
Wales coal-field of 935 square miles, but he estimates the 
total quantity of coal ever held within tEfat basin as only 
16,000 millions of tons ; whereas, Mr. H. Hussey Vivian, in his 
place in the House of Commons, advanced it to 54,000 
millions, and yet more recently Mr. Joshua Richardson, of 
Neath, and Mr. Martin, gave this coal-field an area of 1,055 
square miles, with 64,000,000 tons of coals in each square 
