Vol. 367 No. 9
asked the Minister for Energy if, in respect of each of the ore reserve calculation exercises carried out by personnel of the Geological Survey on all, or parts of the Navan orebody, in the period since its discovery, he will state the figures on tonnage and grade arrived at by ore reserve category.
32.
asked the Minister for Energy if, in respect of the ore reserves within the Tara leasehold which remained to be extracted as of the end of the first operating quarter of 1986, he will (a) state the tonnage and grade in each of the categories of "proven" and "probable" ore reserves and (b) state the definitions of each of the terms "proven" and "probable" as used to calculate the figures being provided.
33.
asked the Minister for Energy if, in respect of the ore reserves within the Bula Limited property which remained to be extracted as of the end of the first quarter of 1986, he will (a) state the tonnage and grade in each of the categories of "proven" and "probable" ore reserves and (b) state the definitions of each of the terms "proven" and "probable" as used to calculate the figures being provided.
I propose to take Question Nos. 31 to 33, inclusive, together. The Geological Survey of my Department carried out certain studies of the ore reserves of Bula Limited in 1980 and 1981. No such studies of the ore reserves of Tara Mines Limited were carried out by the survey. The survey did not break down the Bula reserves into proven and probable categories which, I presume, is the categorisation sought by the Deputy. Following are details of the proven and probable geological ore reserves of Bula Limited and Tara Mines Limited as at 31 December 1985, as furnished to me by the companies. Whilst the figures in respect of Bula Limited also reflect the position as on 31 March 1986, the Bula mine not being in production, the figures in respect of Tara Mines Limited are not available beyond 31 December 1985.
Proven and Probable Geological ore tonnage and grades at 31/12/'85.
|
Proven |
Combined Lead/Zinc grade |
Probable |
Combined Lead/Zinc grade |
Cut Off grade |
|
|
Tara Mines Limited |
11,110,000 |
13.38 |
16,452,000 |
10.40 |
5% combined lead & zinc |
|
Bula Limited |
9,807,000 |
11.70 |
3,207,000 |
7.40 |
4% zinc equivalent |
The reserves were calculated by reference to the US Bureau of Mines definitions of "proven" and "probable" ore reserves.
