New Dolores resource estimates
Minefinders Corporation Ltd MFL
Shares issued 14,171,685
1999-10-06 close $1.12
Thursday Oct 7 1999
Mr. Mark Bailey reports
New resource estimations have been completed for the company's 100-
per-cent owned Dolores property in Chihuahua, Mexico. The revised
resource model constrains the high-grade mineralization within the
Dolores deposit, thereby minimizing the undue averaging of high-grade
ore over a larger area and tonnage.
The total resource defined by the new estimation model (at 0.3 of a
gram per tonne cutoff) is 4.18 million ounces of gold equivalent,
slightly higher than the 3.99-million-ounce resource classified in
1998 (using a 60 to 1 Ag to Au value ratio). Combined measured,
indicated, and inferred resources defined by the revised model are
presented below:
ID5 Resource Estimation 60 to 1 Aueq
Aueq g/t 1000 g/t Oz Au g/t
Cutoff tonnes Au Ag
5.0 3,083 4.30 426,002 266.37
3.0 7,696 2.92 722,725 186.81
2.0 15,526 2.12 1,060,194 133.33
1.0 35,215 1.40 1,586,677 84.46
0.50 59,906 1.00 1,922,718 57.92
0.30 88,884 0.75 2,140,394 42.76
ID5 Resource Estimation 60 to 1 Aueq
Aueq g/t Oz Ag g/t Oz
Cutoff Aueq Aueq
5.0 26,405,116 8.74 866,087
3.0 46,219,209 6.04 1,493,045
2.0 66,552,115 4.35 2,169,396
1.0 95,618,170 2.81 3,180,313
0.50 111,559,193 1.96 3,782,037
0.30 122,192,017 1.46 4,176,928
The new resource model incorporates additional geostatistical
analysis, drill data, geology and refinements to the 1998 estimation
model completed by MRDI, a subsidiary of H.A. Simons Ltd. At the
higher cutoff grades, (that is at a 2.0 g/t Aueq cutoff) the resource
estimate for Dolores increased 19 per cent in gold grade, 44 per cent
in silver grade and 36 per cent in total contained metal from the
1998 MRDI estimate.
Management believes the new model better represents the distribution
and grade of mineralization, corresponding to drill results,
historical mining and the detailed geology of the deposit. At a 5.0
g/t Aueq cutoff, the revised model classified 3.1 million tonnes, at
an average grade of 8.78 g/t (0.25 opt) Aueq, within high-grade
structural zones in the deposit. Historical mining activity at
Dolores from similar high-grade zones produced over 300,000 tonnes
averaging 9.81 g/t Au and 563 g/t Ag, or 19.2 g/t (0.56 opt) Aueq.
Results from more than 50,000 metres of drilling confirmed these high-
grade structural zones over 1,900 metres of strike length. High-grade
gold and silver mineralization extends from the surface to the
deepest drill hole (100 metres below the planned open pit), which
intercepted 11.11 g/t Au and 527.7 g/t Ag over an eight-metre
interval. The reduction in overall tonnage reported at the lower
cutoff grades reflects the new model's ability to better discriminate
between waste, run-of-mine, and high-grade mineralization, thereby
limiting undue averaging of high-grade mineralization with low-grade
and waste material.
The new calculations are based on the database used in the 1998
resource analysis, with the addition of updated hole survey data and
the inclusion of 11 drill holes that were not available at the time
of the MRDI study. The revised model uses an anisotropic search
ellipse that more accurately represents the structurally controlled
nature of the deposit. In total, the resource database now includes
197 drill holes at an average 50-metre spacing along the 1.9-
kilometre strike length of the main deposit.
The new resource model will be incorporated into a revised mine plan,
allowing for optimization of the open pit production schedule and
processing circuit. Additional benefits will include development of
the high-grade underground potential that has been identified beneath
the current open pit design (1.73 million ounces Aueq recovered at a
2.9 to 1 strip ratio) completed by MRDI in 1998.
Increased operational efficiencies related to mining of the higher-
grade resources will allow the company to maximize economic returns
for the project. Additional infill drilling needs to be completed in
order to confirm continuity of the calculated resource prior to
completion of a bankable feasibility.
The Dolores deposit is one of Mexico's largest gold-silver
discoveries in recent times, with excellent potential to
significantly increase the resource with additional stepout
drilling. |
