Gold Exploration in the Dominican Republic
Summary
IMPACT owns a large (21,383 Ha) contiguous package of mineral concessions in the eastern Dominican Republic in the Caribbean Sea. This land package forms a highly prospective exploration area for high sulphidation epithermal gold and porphyry copper-gold mineralization. IMPACT's concessions are underlain by the Early Cretaceous Los Ranchos Formation. Some 100 km to the west, the Los Ranchos Formation is host to Barrick's world class Pueblo Viejo high sulphidation epithermal gold deposit, with 5 million ounces of oxide-hosted gold mined historically and 20 million ounces of sulphide-hosted gold reserves still in place.
The prospective northwest trending structure that controls gold mineralization extends for fifteen kilometers on the property. Further prospecting, geological mapping and sampling around this and other large scale structures and possible intrusive centers are recommended. Elsewhere on the property, the Las Cayas Zone that returned assays up to 44.4 g/t Au and 509 g/t Ag in float boulders, has not been drilled and warrants further exploration.
Introduction
The El Brujo, La Bruja, Tedeche, Baritina, La Culebra and Athena concessions are a 21,383 hectare contiguous land package in the eastern Dominican Republic owned by IMPACT through its Dominican subsidiaries. These five concessions form a highly prospective exploration area for high sulphidation epithermal gold and porphyry copper-gold mineralization in the Dominican Republic.
Regional Setting
The Dominican Republic occupies the eastern two thirds of the island of Hispaniola, located between Cuba and Puerto Rico in the central Caribbean Sea. Hispaniola is comprised in large part of Early Cretaceous to Eocene island arc assemblages and back arc basins, with a strong northwest elongation and structural grain parallel to major fault zones. On the islands of Hispaniola, Puerto Rico and Cuba, mineralization and intrusive activity is known to be focused along northwest trending structures.
IMPACT's El Brujo, La Bruja, Tedeche, Baritina, La Culebra and Athena concessions are cut by several regional scale northwest trending structures and underlain by the Early Cretaceous Los Ranchos Formation. Some 100 km to the west, the Los Ranchos Formation is host to the world class Pueblo Viejo high sulphidation epithermal gold deposit, with 5 million ounces of oxide-hosted gold mined and 20 million ounces of sulphide-hosted gold in reserves
El Brujo, La Bruja and Tedeche Concessions
Drilling in 1996 by BHP Minerals International (now BHP Billiton) at La Bruja (2,222 meters in 10 holes) cut intense argillic (sericite-illite-smectite) to advanced argillic (sericite-pyrophyllite) alteration and high sulphidation mineral assemblages (enargite-pyrite), hosted within quartz plagioclase porphyry, hydrothermal breccia, pyroclastics and schists. Intervals up to 0.97 grams of gold per tonne over 50 meters were cut in core. Mineralization and alteration at La Bruja is focused along northeast and northwest trending major faults. El Brujo is located some 3 kilometers northwest of La Bruja, along strike from the prominent northwest trending Domenica Fault Zone.
A program of surface mapping and sampling at El Brujo revealed widespread gossan and ferricrete float within the area of a 600 by 850 metre soil geochemical anomaly (the "Gossan Zone") as well as 350 by 400 metre soil anomaly some 1.5 km to the southeast (the "Vein Zone"). Mapping and rock sampling established the presence of mineralized outcrop and float in several areas, with values of 3.7 g/t gold, 63 g/t silver, and 2.8 g/t gold and 130 g/t silver in the Gossan Zone and 2.5 g/t Gold in the Vein Zone. Prospecting along the mineralized stratigraphy to the northwest from the grid area resulted in the discovery of anomalous gold in float boulders (up to 3 g/t gold and 3.2 g/t silver) three kilometers northwest of the Gossan Zone. In all areas where mineralization has been discovered, rock exposures are poor, therefore prospecting and float sampling has been the best exploration tool.
In February of 2003, an initial 800m core drilling program confirmed the existence of porphyry copper-gold mineralization. The aim of the drilling was to define the extent and grade of the mineralization in three target areas within the concession. Two holes tested the Dos Brazos Zone where 1999 soil sampling returned values of 3.7 g/t Au, 63 g/t and 2.8 g/t Au and 130 g/t Ag. The holes intersected 24 metres of 0.19 g/t Au and 0.52% Cu. Recent float sampling in the Las Cayas Zone has returned values up to 44.4 g/t Au and 509 g/t Ag but the zone was not drilled.
In early 2008 IMPACT carried out an Induced Polarisation geophysics survey which identified additional anomalies on the concessions.
Baritina, La Culebra and Athena Concessions
Minor grid-based work at Baritina delineated zones of gold-silver-zinc mineralization localized at the intersection of major faults (trench and channel values up to 5.59 g/t gold over 2 m in the North Caracol Creek Zone and 5.35 g/t gold, 39.8 g/t silver and 2.25% zinc over 2 metres in the South Caracol Creek Zone). Limited prospecting over the remainder of the concession, as well as the Athena and La Culebra concessions indicates additional potential for gold, silver and copper mineralization.
The geology, geochemistry and scale of alteration at El Brujo are comparable to the porphyry system on the neighbouring island of Puerto Rico. The Tanama porphyry was explored by Kennecott who defined an inferred and indicated resource of 139Mt grading 0.64% Cu and 0.51 g/t Au for in-situ resources of 2.27Moz Au and 0.889Mt Cu.
