Sierra Madre Developments Inc.

Sierra Madre Developments Inc.

November 16, 2011 09:00 ET

Sierra Madre Developments and Partner Riverside Resources Outline High Grade Silver in Drilling and Trench Results From Jesus Maria Mine Area, Penoles Project, Durango, Mexico

VANCOUVER, BRITISH COLUMBIA--(Marketwire - Nov. 16, 2011) - Sierra Madre Developments Inc. ("Sierra Madre" or the "Company") (TSX VENTURE:SMG) and its partner, Riverside Resources Inc.(TSX VENTURE:RRI), are pleased to announce surface trench and drill results from the Jesus Maria Mine area at the Penoles Project, Durango Mexico. A single hole was drilled to test beneath the historic mine workings and encountered multiple zones of silver-gold with associated lead and zinc mineralization. The trenching delineated aggregate mineralized zones up to 20 meters in thickness (Trench 2), outlined new mineralization along strike, and confirmed previous results, reported by Riverside. Six new trenches were completed by Sierra Madre to bedrock and identified high grade mineralized intervals up to 13.4 meters in width (Trench 4) averaging 1.7 g/t gold, 309 g/t silver, 2.4% lead and 0.6% zinc (including a 6.9 meter interval that averaged 3.1 g/t gold, 552 g/t silver 4.6% lead and 0.6% zinc). Detailed trench assay data is available on the Company's website.

The single drill hole (JM-DDH-11-01) that was completed below the historic mine workings at Jesus Maria encountered the highest individual silver value in this current program (1,757.7 g/t silver from a 0.2 meter wide interval) as well as intersecting three, mineralized intervals with an aggregate thickness of 8.5 meters. The first interval from 156.95 to 159.95 averaged 0.5 g/t gold, 209 g/t silver, 0.6% lead and 0.9% zinc. The second interval from 165.40 to 168.25 averaged 0.2 g/t gold, 86 g/t silver, 1.3% lead and 2.2% zinc and the third interval from 192.40 to 195.05 averaged 0.1 g/t gold, 91 g/t silver, 2.2% lead and 1.9% zinc. The 8.5 meter aggregate assay averaged 0.3 g/t gold, 131 g/t silver, 1.3% lead and 1.6% zinc. Detailed drill core assay data from JM-DDH-11-01 is also included on the Company's website.

Sierra Madre CEO, Carl von Einsiedel, P.Geo. comments: The Penoles project hosts a partially defined oxide gold target (referred to as El Capitan), two historic silver mines (Jesus Maria and San Rafael) and multiple early stage targets within a district scale land package (35,000 ha.) that covers more than half of the historic Penoles Mining District. The thickness and continuity of the mineralized zone observed at Jesus Maria combined with the impressive grades and widths of mineralization encountered during the recently completed drill program at El Capitan (see press release dated October 24, 2011) clearly confirms that the exploration targets at Penoles have exceptional potential.

Trench Program Details:

Previous trench results announced on May 5, 2011 by Riverside at Jesus Maria included 8.3 meters averaging 1.68 g/t gold, 144 g/t silver, 2.4% lead and 2.2% zinc and a second trench with 22 meters averaging 1.08 g/t gold, 224 g/t silver, 2.5% lead and 1.7% zinc. The new trench results expand on this previous work and further define the surface extent of silver, lead, zinc, and gold mineralization within the Jesus Maria vein system.

The surface expression of the Jesus Maria mineralized vein zone is not well exposed and the historic underground mine workings are not presently accessible. The objectives of the trenching program were to assess the grade and continuity of mineralization at Jesus Maria and determine the average width of the mineralized zone. Surface sampling has confirmed that mineralization extends over a strike length of at least 475 meters. Excavator trenching (Sierra Madre Trench No.1 to No.6) and trenching by Riverside (Riverside Trench No.1 to No.4) has confirmed that mineralization ranges from 7.45 to 22 meters in thickness over a strike length of approximately 275 meters. The existing mine workings are located in the northeastern part of one of the concessions under option from Riverside and the surface outcrop of the Jesus Maria is situated near the northern boundary of these concessions. The Jesus Maria concessions extend over a strike length of approximately 1.6 kilometers and cover the projected down dip extent of the Jesus Maria mineralized zone. Additional trenching is planned to continue tracing the western extensions of the mineralized zone.

Summary assay results obtained from the trenching completed by both Sierra Madre and Riverside Resources and the recently completed drill hole will be available on the Company's website at

QA and QC and Qualified Person:

All trench samples were sealed in numbered plastic bags and transported to Inspectorate Assay labs facility in Durango City, a laboratory certified for the provision of assays and geochemical analysis (ISO:9001-2008). All drill core were placed in numbered boxes and transported to Sierra Madre's secure core facilities by the drill contractor. Following detailed core logging all core was split using a diamond bladed core saw under the direct supervision of Sierra Madre's Geologic staff. Half of the core was kept on site in the original core boxes, the second half was placed in labeled and sealed sample bags which were transported directly to the custody of Inspectorate, a laboratory certified for the provision of assays and geochemical analysis (ISO:9001-2008). Samples were transported to Inspectorate's facilities in Durango, Mexico for prep work and analyzed at their facilities in Reno, Nevada. All samples were prepared using standard industry prep methods followed by fire assay analysis and aqua regia digest for trace elements. All samples with greater than 10 g/t Au or 100 g/t silver were additionally tested by fire assay with a gravimetric finish. Sierra Madre has included industry certified Au standards and blanks within the sample stream in addition to field duplicates as part of the QA/QC program.

The scientific and technical data contained in this news release were prepared under the supervision of Carl von Einsiedel, P.Geo and CEO of Sierra Madre.

About Sierra Madre Developments: Sierra Madre is a TSX Venture listed junior mining company based in Vancouver, British Columbia, Canada. Management has extensive exploration and mining expertise and the Company's business model is to acquire advanced gold and silver projects and build shareholder value by rapidly advancing our projects through the resource delineation stage.


Carl von Einsiedel, CEO

Certain statements in this press release may be considered forward-looking information. These statements can be identified by the use of forward looking terminology (e.g., "expect"," estimates", "intends", "anticipates", "believes", "plans"). Such information involves known and unknown risks -- including the availability of funds, the results of financing and exploration activities, the interpretation of exploration results and other geological data, or unanticipated costs and expenses and other risks identified by Riverside in its public securities filings that may cause actual events to differ materially from current expectations. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this press release.

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

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