To: loantech who wrote (15461 ) 7/7/2006 12:32:51 AM From: loantech Read Replies (1) | Respond to of 78411 This says a lot. Let's see if the drill continues to say it is not mined out. If not it is huge and open in all directions but up. << The Sierra Mojada District is located on the southern margin of the Sabinas Basin, a large rift basin in northeastern Mexico, which formed during Late Jurassic and Cretaceous tectonic extension. During Latest Jurassic the Sabinas basin began to form with the basin being dropped down to the north relative to the Coahuila Peninsula that was being uplifted to the south. 1 - Geology Map 2 - Geology Legend Click on Image Section for Close-Up Stratigraphy Upper Jurassic and Lower Cretaceous marine carbonate, sandstone and shale, the La Casita and Menchaca Formations, are overlain by Lower Cretaceous red beds composed of conglomerate, sandstone, siltstone, shale, and tuff, the San Marcos Formation. The San Marcos is overlain by a marine carbonate sequence of Early and Middle Cretaceous age, the Cupido, La Pena, Aurora and Georgetown Formations (refer to district cross section and the geology map). Mineralization Sierra Mojada has two distinct mineral systems separated by the east west trending Sierra Mojada Fault. North of the fault the mineralization is disseminated to massive silver, copper, zinc, lead sulfide (tetrahedrite, sphalerite and galena) deposited in the Menchaca Formation. South of the fault the mineralization is oxide zinc (hemimorphite, smithsonite and sauconite) and oxide lead (cerussite) deposited in the Aurora and La Pena Formations. Click For District Cross Section Close-Up (110k) Cerussite with a high silver content was discovered at Sierra Mojada in 1879 and became known as the Lead Manto. A manto is a near horizontal, tabular body. The Lead Manto has been mined, in an east-west direction, continuously for 3 kilometers and discontinuously for an additional 2 kilometers and was the only source of production from the district until 1906 when copper silver ore was discovered in the San Jose mine north of the Sierra Mojada fault. This discovery started a new period of exploration, discovery and mine development north of the fault. Silver, copper, zinc, lead ore has been produced from over 45 mines north of the fault from 1906 to the present. In the 1920's Penoles discovered oxide zinc ore, hemimorphite, smithsonite and sauconite, deposited in iron oxide, dolomite and limestone units below the Lead Manto that is known as the Iron Oxide Manto. The Iron Oxide Manto has been mined in the San Salvador, Encantada, Fronteriza and Oriental mines, a distance in excess of 2 kilometers. Map of Mines, Workings and Stopes Click for Close-Up(118k) Smithsonite ore was discovered, in the San Salvador mine, deposited in limestone beneath the Iron Oxide Manto and is called the Smithsonite Manto. The Smithsonite Manto is in the basal Aurora Formation and continues into the La Pena Formation and is over 90 meters thick. The Smithsonite Manto has been mined only in the San Salvador mine; it is higher grade than the Iron Oxide Manto, contains very little iron oxide and has been mined for about 400 meters in an east west direction.The Sierra Mojada mineral systems have been mined in excess of 5 kilometers in an east-west direction, 2 kilometers in a north-south direction and 100 meters vertically. The limits of the mineral systems have not been defined in any direction. These two mineral systems have been brought into proximity to each other by post mineral reverse motion on the Sierra Mojada Fault that faults the San Marcos and Menchaca Formations against the Aurora Formation. The San Marcos and Menchaca Formations are 25 million years older than the Aurora Formation. The Sierra Mojada mineral systems are chemical sedimentary and were deposited from metal bearing brines. The deposition of the ore minerals is in temperature equilibrium with the host rocks (iron oxide, limestone, dolomite, carbonate shale and sandstone). There is no alteration, silicification or skarn mineralization. Mineralization has been episodically deposited in certain beds, resulting in a vertical repetition of mineralized beds and ore bodies in the Menchaca Formation and in the Aurora Formation. This intermittent or episodic deposition of mineralization has occurred over at least the 25 million years represented by the age difference in these two formations. It is possible that this process was ongoing during deposition of the other units above the basement rocks. The thickness and character of the rock units below the existing workings is unknown and will have to be determined by drilling. With the evidence of the repetitive nature of the mineralization there is high potential for additional discovery at depth.>>metalin.com