Lago Dourado Minerals Ltd., (the "Company") is pleased to release a geological report by Mr. Simon Meldrum, a geological expert in porphyry-epithermal Au-Cu-Ag systems, on its flagship 100%-owned Juruena Project located in Mato Grosso, Brazil.
The report confirms the porphyry-epithermal potential at Juruena and identifies the Arrastro Hills area as the most promising porphyry target on the property. Drilling to test this new target commenced in January.
Forbes Gemmell, President & CEO, said, "Mr. Meldrum's report is particularly encouraging as it provides further support to the porphyry-epithermal model initially proposed by Professor David Groves when he joined the Company as our Technical Advisor. While drilling to date has already identified seven distinct mineralized zones, the Arrastro Hills target has the potential to represent the 'main prize' given it boasts a classic geological setting whereby a gold-rich porphyry system can be preserved. The geological, geochemical and geophysical datasets are also all supportive of its porphyry potential as outlined in Mr. Meldrum's report. We are excited that drilling is now underway at Arrastro Hills and look forward to systematically drill testing this new target over the coming months."
Mr. Meldrum conducted a six-day site visit to Juruena in mid-December. Mr. Meldrum is a consulting geologist with more than 30 years experience focused on porphyry-epithermal systems working for major, mid-tier and junior exploration companies. He has participated in the discovery and evaluation of large-scale porphyry and epithermal gold systems, including Batu Hijau (Indonesia) and Rio Blanco (Peru). Mr. Meldrum's report (available at www.lagodourado.com under Projects-Juruena-Reports) describes his preliminary findings on the Juruena Project and is not a "Technical Report" as defined under NI 43-101.
In his report, Mr. Meldrum concludes that there is little doubt that a porphyry intrusion with the potential to produce high-sulfidation epithermal gold mineralization is concealed under the lithocap at Arrastro Hills based on the extensive clay-silica alteration, multi-element zonation, variable intrusive rock types and magnetic and radiometric characteristics. It is inferred that the intrusion was emplaced at a high crustal setting (near surface) during a period of rapid uplift and erosion, a tectonic environment not dissimilar to the current day Andes mountain chain in Chile.
Highlights from the Arrastro Hills target area and the rationale for its potential to host a gold-rich porphyry-epithermal system are outlined as follows (and in Figure A: http://media3.marketwire.com/docs/ldm_225_figure_a.pdf):
- The presence of a lithocap which, in most instances, is considered to develop over mineralized porphyry intrusions. The evidence for a lithocap is supported by widespread and intense acid alteration that is coincident with a potassium radiometric anomaly and elevated barium and arsenic soil values. The porphyry stocks that generate such lithocaps are typically high-level (within 200m to 800m from surface). Under the right conditions, mineralization directly beneath the lithocap may be enriched.
- Multi-element zonation from geochemical soil sampling is consistent with a well-developed epithermal-porphyry system. Elevated background Ba and Pb soil values define the limits of the lithocap, while elements associated with possible epithermal leakage (As-Ag-Bi-Hg-Mo-Pb-Sb) from the underlying porphyry are anomalous in the centre of the system. Gold and Cu are interpreted to be both depleted from the regolith due to mobilization relating to the intense acid alteration formation of the lithocap.
- The airborne magnetics shows a circular magnetic high at Arrastro Hills, which is interpreted to be the primary heat source or causative porphyry intrusion.
- Arrastro Hills is located in close proximity (<2km) to the Crentes Domain (see Figures B and C: http://media3.marketwire.com/docs/ldm_225_figure_b_c.pdf), which is interpreted to be a deeply eroded porphyry system, suggesting similar mineralizing events were also active at Arrastro Hills at the time of formation. In contrast to the eroded Crentes Domain, the presence of a lithocap at Arrastro Hills provides an excellent geological setting whereby a gold-rich porphyry system can be preserved.
Juruena Geological Model
Based on a thorough assessment and evaluation of the geological, geochemical, geophysical datasets and analysis of drill core, Mr. Meldrum identified not one but three distinct porphyry domains within the Juruena project area (as outlined below). Each porphyry domain is bounded or separated by a major fault which, due to the tectonic environment in action (uplifting and erosion) at their emplacement, has resulted in three very different porphyry settings.
- Arrastro Hills - lithocap associated with a near-surface porphyry intrusion as outlined above.
- Crentes Domain - an extensive Au-Cu-Mo soil anomaly that is interpreted to be a deep seated detached porphyry system that has since been uplifted and eroded. Under such a model mineralization is focused predominately along structures at the edges of the porphyry system (i.e. Tomate, Crentes and Mauro Zones) and further mineralization could be expected along these gold-bearing structures and/or at depth. Later-stage intrusions including lamprophyres and other mafic dykes account for mineralized zones such as Uiliam (216m @ 0.55g/t Au).
- Noventa Graus Porphyry Domain: a structurally controlled extensive NW-SE trending zone of elevated As with strong Au and Mo-Cu values situated adjacent to a large intrusive heat source. This target is largely untested although an isolated shallow RC drill hole returned an intercept of 25m @ 1.01g/t Au at a depth of 20m.
Drilling for 2013 is underway with one drill rig turning on the first hole at the Arrastro Hills target. Drilling to date on this first hole has been slower than expected. This has been a function of fractured ground encountered at the top of the hole as well as trying to ramp up drilling in a new target area in the wet season. Drilling productivity is expected to improve as the wet season subsides (March onwards). Approximately 5,000 metres is still to be drilled as part of the Company's Phase 2 drill program.
Murray Paterson, P.Geo, Vice President Exploration and Development for Lago Dourado Minerals Ltd, is the Qualified Person, within the meaning of NI 43-101,who reviewed the technical data in this news release.