A first round of drilling of the Venturina gold-silver target in the northern Mexican state of Chihuahua has returned mixed results for
The Vancouver-based junior drilled 13 holes totalling 1,650 metres while testing a 400-metre strike length of the main Venturina prospect. Eight of the holes intersected intervals the company deems as significant.
Situated in the Sierra Madre Occidental province, the property occupies a portion of the historic Dios de Guia gold-silver district. While there are abundant small to moderate size mine workings on the property, Northair is the first to conduct modern exploration.
The company is targeting the main Venturina zone for its bulk-tonnage potential. Mapping and sampling have traced the main target over a strike length of 1,650 metres and a width ranging from 15 to 100 metres. Mineralization occurs along a complex, northwesterly striking normal fault zone that contains several closely spaced sub-parallel faults, most of which have been altered and silicified.
More than 400 chip and channel samples returned an average grade of 1.67 grams gold and 39 grams silver per tonne.
More recently, 124 samples collected from historic workings in the zone averaged 3.03 grams gold and 59 grams silver. Results from the sampling of three small shafts included: 20 metres averaging 6.2 grams gold and 83 grams silver; 38 metres averaging 1.71 grams gold and 24 grams silver; and 47 metres averaging 4.24 grams gold and 109 grams silver.
The initial drilling tested the northwesterly trending zone at right angles. The first hole was oriented to the southwest and cut the zone at an angle of minus 75, intersecting 9.1 metres of 1.41 grams gold and 15.4 grams silver, starting at a down-hole depth of 38.1 metres.
Stepping out along strike 50 metres to the northwest, the rig was swung 180 about so that holes 7 and 13 were drilled to the northeast. The two holes intersected post-mineral rhyolite dykes, with hole 7 undercutting hole 13. A further 20 metres to the northwest, hole 2 encountered only anomalous values.
Hole 3 was collared a further 40 metres along strike and drilled at an angle of minus 45 to the northeast. The hole cut 3 metres of 1.09 grams gold and 15.2 grams silver at a downhole depth of 29 metres. Hole 4 undercut hole 3 but intersected only anomalous grades.
Hole 5 was drilled at minus 45, about 65 metres along strike of hole 4. It hit 13.7 metres averaging 0.89 gram gold and 30.6 grams silver, starting at a depth of 83.8 metres.
Stepping out a further 40 metres to the northwest, hole 6 was drilled at an inclination of minus 60 and encountered a near-surface 53.3 metres averaging 1.3 grams gold and 29.6 grams silver (including a 22.9-metre intercept of 2.89 grams gold and 65.1 grams silver), beginning at a depth of 3.05 metres.
Hole 8 stepped out 47 metres along strike of hole 6 and intersected 4.6 metres grading 0.96 gram gold and 28.8 grams silver at a down-hole depth of 56.4 metres.
A further 22 metres to the northwest, the rig was swung around 180 and hole 9 was drilled to the southwest at minus 45. The hole intercepted 10.7 metres averaging 1.61 grams gold and 30.3 grams silver, beginning at a depth of 9.1 metres.
Hole 10 stepped out 20 metres northwest of hole 9; it was drilled to the northeast at an inclination of minus 60, cutting 3 metres grading 0.82 gram gold and 53.8 grams silver at a depth of 18.3 metres.
Hole 98-11 was aimed to the southwest at minus 60, about 40 metres along strike of hole 10. It intersected a near-surface 15.2 metres averaging 1.88 grams gold and 21.5 grams silver (including a 6.1-metre interval averaging 4.6 grams gold and 50.2 grams silver), beginning at a depth of 1.5 metres.
Stepping out a further 48 metres to the northwest, hole 12 hit an uncut 25.9 metres averaging 3.4 grams gold and 16.2 grams silver (including 13.7 metres averaging 6.21 grams gold and 29.2 grams silver), starting at a downhole depth of 18.3 metres. If cut to 10 grams gold, the 25.9-metre interval averages 1.45 grams gold.
Preliminary metallurgical bottle-roll testwork performed on surface and underground samples indicates recoveries in the order of 89% for gold and 88% for silver.
Northair says it is encouraged by these initial results and notes that further drilling will be necessary to evaluate not only Venturina but four other prospects, all of which are to undergo further mapping and sampling. The company is currently planning its 1999 exploration program.
A table of the significant drill results is shown below:
HoleAngleDepthFromToIntervalGoldSilver
(degrees)(m)(m)(m)(m)(g/t)(g\t)
98-17571.633.547.213.70.9612.3
including38.138.147.29.11.4115.4
98-34541.229.032.03.01.0915.2
98-545 99.083.897.513.70.8930.6
including85.394.59.21.2140.5
98-66059.43.156.453.31.3029.6
including33.556.422.92.8965.1
98-86065.544.264.019.80.3411.8
including56.461.04.60.9628.8
98-94553.39.119.810.71.6130.3
including13.719.86.12.7451.9
98-106050.318.321.33.0 0.8253.8
98-116047.21.516.815.21.8821.5
including1.57.66.14.6050.2
98-126059.418.344.225.93.4016.2
including18.332.013.76.2129.2
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