Status: Available for Option
The target at El Pima is shear hosted quartz stockwork gold and distal sediment hosted disseminated gold deposit. One kilometer north of El Pima in the San Manuel zone disseminated and quartz stockwork gold have been reported by the Mexican Geological Services (SGM).
Location and Setting
El Pima is located in the Santa Teresa mining district in northern Sonora 39 km south of Magdalena and 5.5 kilometers south of GoGold’s Santa Gertrudis mine.
El Pima consists of one claim covering 70 Ha. The claim is surrounded by First Silver Reserve and by Teck Resources claims which contain numerous color anomalies.
Some of the first exploration in the district was performed by Phelps Dodge in the 1980s. A major discovery just 6 km north of El Pima was made in 1986 and became the Santa Gertrudis mine which Phelps Dodge exploited between 1991 and 1994. This mine produced 564,000 oz. grading 2.13 grams Au/ton between May 1991 and October 2000.
The El Pima claim is in the heart of the Santa Teresa Mining district which lies in the transition zone between the Basin and Range and the Sierra Madre Occidental. The lithologies in this areas include sedimentary rocks that are surrounded and partially covered by Oligocene volcanic rocks. All units are cut by andesite to rhyolite composition dikes. Intrusive rocks include diorite stocks and sills and granite. Lower to middle Cretaceous Bisbee Group sedimentary rocks host the majority of gold mineralization.
Structure and Alteration
Silicification is the most notable style of alteration at El Pima. It occurs as jasperoidal replacement bodies and as quartz veins. Oxidation, when it is present, is represented by hematite, limonite and goethite. Regionally, the area is dominated by north trending basin and range style topography. However locally the structure is more complex. Folded rocks are cut by steeply dipping northwest trending normal faults, northeast trending faults and further dissected by strike slip movement.
Gold mineralization is commonly associated with silicification. Field mapping in the area suggests that veining, silicification and gold mineralization occur within dilational shear zones in calcareous sedimentary rocks containing localized quartz stockwork and silicified breccia lenses.
Conclusions and Recommendations
Mineralization at El Pima is commonly associated with narrow shear hosted veins in calcareous sedimentary unit. This geology is similar to the geology of the Santa Gertrudis mine which boasts reserves of 810,000 oz. Au indicated. In order to target a potential ore body like Santa Gertrudis more work will need to be performed. Preliminary recommendations include stream sediment sampling, mapping, rock chip sampling and soil grid sampling.
“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.”