The latest assays from Alder Resources’ Rosita copper-gold-silver project in Nicaragua shows the company could well be on its way towards getting the site back into production.
The assay results come out of the last six holes in the first phase of diamond drilling and were highlighted by an assay of 10 metres grading 1.42% Cu, 0.18 g/t Au and 20.45 g/t Ag.
That high grade intercept came within a wider interval that graded 0.50% Cu, 0.08 g/t Au and 6.44 g/t Ag over 53 metres.
Mineralization was struck roughly 120 metres below the base of the historic Rosita pit in an area that is known as Santa Rita. Alder says mineralization is hosted in skarn and that the recent intercepts lie below the central part of the pit.
The average intercept width of the higher grade intercepts is 10.3 metres and together they define a strike length of 250 metres, and occur over a vertical range of roughly 150 metres.
When combined with other results released earlier from the same drill program the company has traced mineralization over a strike of 1,100 metres and to a vertical depth of 200 metres.
Rosita also has a stockpile resource of 7.95 million tonnes grading 0.62% Cu, 0.46 g/t Au and 9.20 g/t Ag and Alder says the material could serve as a source of low cost mill feed.
But Santa Rita didn’t hold the totality of the prospective results. Roughly 4 km northwest of Rosita at the Bambana prospect Alder put two holes in the ground and the core came back with intercepts of 13 metres grading 1.23% Cu, 0.36 g/t Au and 10.63 g/t Ag and 18 metres grading 1.74% Cu, 0.09 g/t Au and 16.65 g/t Ag.
In the case of both holes mineralization began at surface and is localized in variably oxidized and clay-weathered potassium feldspar-quartz altered andesitic volcanics and diorite containing copper oxides and minor sulphides.
The first phase of diamond drilling was made up of 20 holes covering 5,908.5 metres. A full 18 of those holes were collared in the Santa Rita area with the final two going into Bambana.
Alder says that all of the holes intersected varying levels of copper, gold and silver mineralization.
The company is putting more capital into Bambana as it is now doing geologic mapping, soil sampling and running a trenching program to test several high quality IP geophysical anomalies, and high grade copper-gold bearing grab samples from the highly prospective Bambana
Past trenching at the zone returned 3.32% Cu, 0.22 g/t Au and 37.55 g/t Ag over 12 metres. Alder says the zone appears to be related to porphyry style mineralization.
Alder signed an option agreement with Calibre Mining in August of last year that allows it to earn a 65% interest in the 33.56 km2 Rosita D concession, which sits within Calibre's wholly owned Borosi concessions.
To move up to that interest Alder has to spend $4 million on exploration and issued 1 million of its shares to Calibre over four years.
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Oliver Maki P.Geo.
I was underground at the Rosita workings, such as they were, in 1950. Some of the finest specimens of malachite and chalcocite were found there. The malachite was of premium gem quality however its worth in that context was not recognized at that time. Sadly it has probably all gone through the crusher since. Pleased to hear the merits of new ore at depth are finally coming to light.