Los Cuarentas Oeste
Status: Under Option to Centerra Gold
Targets at Los Cuarentas Oeste include epithermal gold/silver and carbonate replacement deposits.
Location and Setting
The Los Cuarentas Oeste project is located approximately 160 km northeast of Hermosillo in Northern Sonora, Mexico.
The Los Cuarentas Oeste Project consists of three claims totaling 10,038 hectares controlled 100% by Recursos Millrock, subject to production royalties of 1.5% on gold and 1% on other metals. The claim block surrounds an internal, third party claim (Santa Rosalia) of 87.7 hectares.
Significant exploration has been done in the project area. Stream sediment, soil and rock sampling were completed with follow-up drilling on select targets. The database currently contains roughly 620 rock samples, 255 stream silt samples, and 360 soil samples. Drilling totalled 2,188 m in 14 drill holes in four different target areas.
Geology and Mineralization
Bedrock comprises a plunging anticline or dome exposing rocks of Early Cretaceous through Tertiary age which are overlain to the southeast by younger Baucarit conglomerate. The oldest exposed rocks are Lower Cretaceous clastic sedimentary rocks and limestone overlain by Upper Cretaceous to Paleocene volcanic rocks consisting of green to maroon andesite, minor dacite to rhyolite, green to grey green sandstone and some minor lensoidal intercalated limestone. The Upper Cretaceous volcanic rocks are in turn overlain by a thick pile of cliff – forming, pale weathering felsic tuffs assigned an Oligocene age.
Los Cuarentas Oeste hosts an extensive system of epithermal veins exhibiting boiling textures and abundant carbonate, suggestive of high levels of deposition. To date, seven different vein systems over an area measuring eight kilometers by six kilometers have been identified. The veins rarely contain ore grade mineralization at surface, although select samples have returned up to 7 gpt Au. An internal, third party claim covers the past-producing Santa Rosalia vein system. A Millrock claim covers a portion of the eastern projection of these veins where grades on surface of 9.4 gpt Au and 109 gpt Ag over 3 m were encountered. Additional showings to the north are hosted in calcareous mudstone and limestone where exploration suggests potential for disseminated Au‐(Ag‐As‐Sb) mineralization.
Although initial drill testing of the vein systems at Los Cuarentas Oeste failed to intersect ore grades and widths, the Project warrants follow up exploration. Additional, detailed mapping and structural analysis is required to better understand the geometry of the vein systems, particularly as they project to depth. This cost-effective exploration would likely lead to further drill targets. In addition to the epithermal vein targets, the northern part of the Project Area contains multiple, silicified ledges anomalous in Au‐Ag‐Sb‐As, and the area is deemed prospective for carbonate hosted, gold-silver mineralization.
Agreement and Terms
The project is currently under an option to joint venture with Centerra Gold.
“THE TECHNICAL INFORMATION WITHIN THIS DOCUMENT HAS BEEN REVIEWED AND APPROVED BY GREGORY A. BEISCHER, PRESIDENT & CEO OF MILLROCK RESOURCES INC. MR. BEISCHER IS A QUALIFIED PERSON AS DEFINED IN NI 43-101.”