Piedra Iman Project, Nicaragua
The Piedra Iman project is located about 100 kilometers (km) northwest of Managua, Nicaragua via the Pan American Highway. The project is 30 km north of B2 Gold's El Limon Mine, in a region historically developed with small artisanal gold mines. Over 80 small gold processing plants (arrastras) were reported working in nearby areas outside of Caza's holdings. Caza, through its Nicaraguan subsidiary Nicaza, controls 100% of the 7947.27 hectare Aguas Calientes Concession encompassing the Piedra Iman prospect and adjacent exploration targets.
A literature reference to a copper-gold project explored pre-civil war in the 1970's led to Caza's Nicaragua geologic team discovering several old exploration drill sites and the collapsed portal of a reported 600 meter long exploration tunnel. The exploration was reportedly done by Laminex, a subsidiary of former Noranda Ltd., which operated El Limon at the time. Caza has been able to obtain a few old files from the work, but to date the company has been unable to secure the critical information from the historic work.
Recent exploration under Caza Gold has included stream sediment sampling, soil sampling, and geologic mapping combined with rock sampling. Stream sediment sampling was wide-spread, reconnaissance style sampling, and produced a number of gold and copper anomalies that have not yet received follow-up work. Soil sampling was completed on a nominal 50m x 100m grid over part of the Piedra Iman target. The soil grid however, covers only part of the target and remains open with anomalous results in a number of areas. Caza recently completed semi-detailed geologic mapping over the main anomalous area, with detailed (1:1000 scale) mapping in select areas.
Geology and Alteration
Piedra Iman is underpinned by a Tertiary intrusive complex comprised of multiple phases of diorite to quartz diorite porphyry. The diorite – quartz diorite porphyry phases have been intruded by granite and aplite. The entire intrusive complex is broken by a system of faults striking N, N30°E and N60°W. The granite in places appears cut by smaller, late-stage diorite plugs and dikes. The northern and southern parts of the prospect are blanketed by colluvium, so the bedrock is poorly understood.
Copper-gold-molybdenum mineralization appears associated with at least two magmatic- hydrothermal events at Piedra Iman, including an early, multi-phase, diorite to quartz diorite porphyry system, and a later, granite-aplite intrusive system.
Hydrothermal alteration mapped across the granitic intrusive system includes a central zone, containing secondary biotite with quartz occurring principally in veinlets and vein breccias. Frequently the biotite is retrograded to chlorite and magnetite chlorite. In outline, the areas of secondary biotite (3 mapped) form lenticular bodies up to 250 m long x 80 m wide. Perhaps most importantly, the secondary biotite zones appears to define areas most favorable for mineralization, and where intense chalcopyrite-bornite mineralization is present as disseminations and veinlets. The biotite zone is flanked by a broad halo of sericite/illite-clay alteration containing in places quartz, tourmaline, magnetite, specularite, chlorite and sulfides, as disseminations, in cavities, and in veinlets.
At this point there is little information on the alteration in the diorite – quartz diorite porphyry phases as outcrop is scarce and little mapping has been completed therein. Alteration mineralogy noted in the diorite-quartz diorite porphyry complex is a variable combination of albite, magnetite, actinolite, chlorite, and epidote, based on field mapping to date. Alteration is manifested as veinlets, disseminations, and in cavities. Further detailed mapping is required to better classify this alteration.
Mineralization and Surface Geochemistry
Mineralization noted on surface occurs in fractures and veinlets, as well as disseminations, blotches, and infillings. Mineralization is primarily in sulfides with local areas of oxidation. The sulfide assemblage is dominated by chalcopyrite and pyrite with bornite and molybdenite in places. Molybdenite has been noted only in the granitic phase, thus far.
Numerous veinlets were mapped over the property, with veinlet density increasing near structural zones, intersections, and areas of intense alteration. Quartz-magnetite veinlets and irregular infillings appear to have formed early, followed by quartz-specular hematite veins. Areas of mineralization contain quartz +/- chalcopyrite +/-bornite +/-pyrite in veinlets, and in the higher grade areas the veinlets appear superimposed on an earlier magmatic mineralizing event. Molybdenite was noted in some veinlets.
Soil sampling completed thus far shows a large Cu and Au anomaly over the main area of alteration and extending into the surrounding unmapped areas. Rock chips as well show anomalous Au, Cu, and Mo. Anomalous Au and Cu values are found throughout the granite and diorites, reaching the best grades in the highly altered, brecciated granites where values up to 60 g/t Au and over 1% Cu occur on surface.
Initial reconnaissance in the Aguas Calientes concession has discovered a large area of Cu-Au+/-Mo mineralization at the Piedra Iman prospect. Thus far an area of at least 1000 m by 300 m has been defined with alteration in granitic and dioritic intrusive rocks along with strongly enriched Cu and Au in soil and rock samples. The mineralized zone is open at this point, as is the remainder of the concession where anomalous values in isolated stream and rock samples remain to be followed up.
The mineralization at Piedra Iman appears to be porphyry-type Cu-Au-Mo overprinted and perhaps enriched in places by intrusive-related breccia bodies. The large size potential along with the high grades suggest a major exploration target with high potential for a significant discovery. Caza Gold plans further work on the target including detailed mapping and sampling, trenching, and geophysics, followed most likely by drilling. Caza is currently initiating plans for this work and has started the permitting process for an EIS drilling permit.