Mar-West drilling tests Cerro Blanco discovery

Encouraged by results to date from the Cerro Blanco gold discovery in southeastern Guatemala, Mar-West Resources (MSR-V) is planning its next phase of drilling.

Cerro Blanco is a hot spring gold prospect situated 4 km from the Pan American Highway, not far from the town of Asuncion Mita. It forms part of the 3,900-ha Jutiapa II concession, held 100% by Mar-West.

Geochemical and geophysical studies first defined a target area with a north-south-trending strike length of about 2.8 km. Coincident gold and arsenic anomalies are associated with the southern and northern portions of the trend. The southern end, dubbed the 620 Hill zone, is covered by a flat-lying sinter block 15 to 20 metres thick that outcrops over a length of 1,100 metres.

The northern end has been more difficult to interpret, as it is covered by a boulder field of sinter and has little outcrop.

To date, the Vancouver-based junior has completed nine reverse-circulation (RC) holes totalling 1,350 metres. All but one of the holes targeted the 620 Hill zone.

Among the latest batch of drill results were those of hole CB-8, which intersected 158.5 metres averaging 1.68 grams gold per tonne uncut (1.5 grams cut), beginning at a downhole depth of 29 metres. As with previous holes, the gold grade in hole 8 increases with depth. It includes a 74.7-metre interval averaging an uncut 2.79 grams gold (2.4 grams cut), starting at a depth of 112.8 metres.

For analysis, 104 samples were taken from hole 8 at 1.52-metre intervals.

The results were cut arbitrarily at 10 grams. Only two of the samples exceeded this limit, with grades of 28.34 and 11.17 grams.

Hole 8 was drilled to the east on grid line 7100 at minus 60, undercutting previously reported holes 1 and 2. Collared at an angle of minus 45, Hole CB-1 intersected 73.2 metres averaging 0.75 gram gold, starting at a downhole depth of 25.9 metres. Drilling problems stopped the hole in hydrothermal mineralization at a downhole depth of 99.1 metres.

The second hole stepped back 35 metres to the west and undercut hole 1 at minus 60, returning 111.3 metres averaging 1.48 grams gold, starting at a downhole depth of 21.3 metres. The bottom 50.3 metres of the hole averaged 2.57 grams gold. Hole 2 ended in mineralization as well.

Hole 8 stepped back 35 metres west of hole 2. Mar-West initially tried to drill the site of hole 8 with a diamond drill, but the rig experienced difficulties drilling through the sinter and was forced to switch back to reverse circulation.

Robert Wasylyshyn, vice-president of exploration, said that in the next round of drilling, Mar-West will probably use the RC rig to hammer through the first 25-30 metres of sinter before dropping a core barrel down for the first couple of holes.

Based on drill results to date, the mineralized structural corridor is interpreted by company geologists to dip 60 to 70 to the west, with section 7100 having a true width of 135 metres. Mineralization remains open to the west, at depth, and to the north and south.

Wasylyshyn says the interpretation is based on lining up the assays of the three holes on section. “That is a very unfortunate thing to have to do, but it’s probably a high-angle system cutting low-angle stratigraphy, which means that you can’t line up strata, and because we’re dealing with [rock] chips, we don’t have a lot of geological data,” he adds.

To date, only 500 metres of strike length along the north-south-trending corridor have been tested. Hole CB-3 was a 300-metre stepout north of holes 1 and 2. It intersected a previously reported 91.5 metres averaging 0.67 gram gold, beginning at a downhole depth of 41.1 metres. Hole CB-5 stepped out a further 200 metres to the north and cut a previously reported 47.2 metres averaging 1.43 grams gold, starting at a depth of 36.6 metres, including a 12.2-metre intercept grading 2.28 grams gold between 71.6 and 83.8 metres down. Both of the holes were drilled at minus 50.

During recent drilling, hole CB-7 and CB-9 were designed to undercut hole 3 on grid line 7400. However, Hole 7 was lost in a fault at a depth of 51.8 metres, just as it was cutting into the zone. The bottom 32 metres of the hole averaged 0.46 gram gold, with the final 9.1 metres running 0.77 gram.

Collared at minus 45, hole 9 stepped back 75 metres west of hole 3 and encountered 42.7 metres grading 0.47 gram gold, beginning at a downhole depth of 109.7 metres. Mar-West says hole 9 appears to be in an area of structural complexity. The deeper geophysical data in this area is offset, which is possibly a reflection of deep faulting. Hole 7 was lost in the vicinity in a large cavity, which Wasylyshyn suggests is evidence of post-mineral faulting.

A parallel geophysical target 200 metres west of the main mineralized corridor was tested by hole CB-6. The hole, which was drilled to the west, returned no significant values.

Only one hole has been drilled in the north block. Hole CB-4 was collared 1,600 metres to the north of hole 1 and drilled to undercut a mineralized trench that averaged a grade of 1.37 grams across 45 metres. Hole 4 intersected a 15.2-metre interval grading 0.79 gram, beginning at 47.7 metres, as well as a 13.6-metre interval averaging 2.17 grams, starting at 134.1 metres.

Drill samples were sent to TSL Laboratories’ sample preparation facility in Tegucigalpa, Honduras, before being split and shipped to TSL’s Saskatoon lab for standard fire assay with a gravimetric finish. Mar-West carried out check sampling and metallic gold re-assays for confirmation.

Having received all the results from the initial program, which Wasylyshyn describes as one of wide-spaced reconnaissance drilling, Mar-West is contemplating using a bigger rig to drill deeper holes and stepouts in the next round of drilling. A quality-control and quality-assurance sampling program will be implemented in the next phase.