Millrock Resources Inc. is pleased to report that the first phase of surface exploration on the La Navidad gold project is near completion, and a drilling program has begun.
The project, located in Sonora State, Mexico, 100 km north of the City of Hermosillo, targets orogenic gold deposits. Highlights of a rock sampling program include:
- 24 meters grading 0.9 grams per tonne gold;
- 12 meters grading 1.1 grams per tonne gold;
- 14 meters grading 0.8 grams per tonne gold.
A drilling program consisting of approximately 2,000 meters in nine drill holes is in progress and is planned for completion in December.
Since forming an option to purchase agreement with the underlying mineral right owner in June 2017, and a simultaneous option to joint venture agreement with Centerra Gold Inc. ("Centerra"), Centerra and Millrock have collaborated to execute a comprehensive exploration program. Centerra is funding the exploration work to earn an interest in the project.
The La Navidad project targets bulk minable, run-of-mine, oxidized deposits that could be processed by heap leaching. The prospects at La Navidad bear the characteristics of an orogenic gold system similar in nature to other gold deposits being mined in the district, including:
- Lluvia de Oro (Metallōrum Holding);
- Santa Gertrudis (Agnico Eagle Mines Limited); and the
- San Francisco Mine (Alio Gold Inc.).
Alio Gold's San Francisco Mine is a prime example of the type of deposit sought by Millrock and Centerra. On their website, Alio Gold reports:
- Measured & Indicated Resources (inclusive of Reserves) - 74.8 million tonnes grading 0.541 grams per tonne gold, containing 1.3 million ounces of gold
- Proven & Probable Reserves - 54.8 million tonnes grading 0.527 grams per tonne gold containing 0.9 million ounces of gold.
Exploration Program and Summary Results:
Soil sampling across the entire property was successfully completed. In total, 1,082 samples were collected and 886 samples have been analyzed. Results are still pending for 196 samples. Of the samples that have results, multiple zones of anomalous gold in soil were identified, with 248 of the 886 analyzed samples containing in excess of 50 parts per billion gold.
Three main prospect areas have been identified -- Anchor, Horseshoe, and Cobre -- and these are described in more detail below.
Magnetic geophysical surveys (82 kilometers) and dipole-dipole induced polarization ("IP") geophysical surveys (20 kilometers) were carried out to image bedrock features beneath surface. Magnetics helped map the lithological units. IP identified zones of strong chargeability and supports an interpretation of gently-dipping rock units. Known gold mineralization is hosted in low to moderately resistive rock units, enclosed above and below by moderately resistive rocks.
Geological mapping was carried out across the entire property. The geology is complex and contains multiple deformed rock types. Biotite gneiss and metasediments are intruded by granodiorite, diorite and granite. Hydrothermal alteration is widespread in these rocks and corresponds to northwest trending and northeast trending structural zones. Mineralization appears to be associated with iron carbonate minerals (siderite predominantly), fine disseminated pyrite, with sericitization and silicification of the metasedimentary and gneissic host rocks.
The numerous roads and trails present on the property were upgraded and refurbished with a bulldozer, creating continuous rock exposures in altered and mineralized zones. Detailed mapping was done along rock exposures in road cuts. Continuous chip-channel rock sampling was also done along the road cuts and strongly anomalous gold was detected over significant widths, as outlined under the prospect descriptions below. A total of 575 rock samples were collected. Of these, 83 samples contained gold grades above 0.5 parts per million (ppm) and 49 of the samples contained more than 1.0 ppm.