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Cinco de Mayo
CINCO DE MAYO PROPERTY
MUNICIPIO VILLA AHUMADA CHIHUAHUA, MEXICO
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Cinco de Mayo is a 5,000 hectare Carbonate Replacement Deposit ("CRD") prospect located in north-central Chihuahua, identified by drilling in late 2007, and 100% owned by MAG Silver.
Early regional exploration work and results of initial drilling clearly show that Cinco de Mayo has many geological and mineralogical characteristics in common with the largest CRDs in Mexico.
In less than a year of drilling a coherent massive sulphide sheet ("manto") with a strike length of at least 2,000 metres which remains open along strike and to the southwest has been defined; returns are notable for high grades of zinc and lead, along with the high-grade silver. Latest results also show significant gold values. Hole 08-48 reported 1.50 metres of 6.89 g/t (0.20 opt) gold, 370 g/t (10.8opt) silver, 19.15% lead and 9.46% zinc. The latest holes contain scheelite (tungsten)-bearing skarn, suggesting we are homing in on the source of the mineralization.
The successful locating of completely blind mineralization in initial drilling, along with latest drilling results, confirms that we are applying the right techniques in the right geological setting, and that a mineralized carbonate replacement system of significant strength and size is being outlined.
Carbonate Replacement Deposits (CRDs): Renewed exploration focus
Carbonate Replacement Deposits (CRDs) represent approximately 40% of Mexico's 10-billion ounce historic silver production. They are characterized by massive to semi-massive silver-lead-zinc sulphide intrusions; these metal-rich intrusions replace the carbonate host rocks (limestone). CRDs occur along major regional structures, and Cinco de Mayo lies along the same NW-trending regional structure that hosts several of the largest CRDs in Mexico.
Cinco de Mayo is one of three (3) 100%-owned CRD properties MAG Silver is exploring. Though they've been mined in Mexico for more than 400 years, CRDs are now receiving renewed attention. Today's higher base and precious metal prices are one important factor. Additionally, the application of modern geoscience makes detection of sulphide systems at depth more possible than in the past.
Other attractive characteristics of CRDs include: potential for large tonnage and high grades; potential for substantial base metal credits to the precious metal resource; and, sulphide replacement in carbonates (limestone) mitigates oxidation, and is therefore more metallurgically amenable and environmentally benign.
Background: Cinco de Mayo, a regional story
At Cinco de Mayo the regional story is very strong: the project lies on the western bounding fault of the Chihuahua Trough, the same structure that hosts major CRDs like Santa Eulalia (MAG's Guigui property), Naica, San Pedro Corralitos and Terrazas. This gives rise to a thick carbonate section to host mineralization and a major regional zone of weakness for both ground preparation and intrusive emplacement.
This ancient crustal break first controlled deposition of a thick section of carbonate host rocks, later movements created abundant structural fluid pathways, and finally it guided metals-rich magmas into place for optimal mineral deposition.
At Cinco de Mayo there are numerous mineralization and alteration occurrences associated with this fault. These include old mines on the Cinco Chimney and Cinco Manto at opposite ends of the Cinco de Mayo Ridge, Abundancia, Celia and Orientales, all of which lie within MAG's property package. Further, Cinco de Mayo Ridge is cut by numerous ferruginous jasperoid veins that carry strongly anomalous lead-zinc-copper-silver and gold values. Despite the extensive cover, the nature and degree of mineralization and alteration in Cinco de Mayo Ridge strongly indicated that a significant CRD system may lay hidden nearby under the cover.
2006: Concept to discovery
The Cinco de Mayo discovery in 2006 was particularly significant, achieved as it was by "blind" drilling. The property is 75% covered with alluvium, with virtually no outcrop to guide exploration. All of the mineralization intersected to date was initially identified as buried (blind) geophysical and geochemical anomalies consistent with our exploration model.
Prior to drilling, in order to "see" below the alluvial cover, MAG conducted extensive geological, geochemical, biogeochemical and geophysical studies. From interpretation of this data MAG developed a series of drill targets along a very prominent NW trending fault zone that cuts strongly folded massive limestone and limestone-rich sedimentary rocks. Nine holes totaling 3,975 metres were drilled in an area roughly 1.5 kilometres wide and over 2 kilometres long, with six of the holes returning replacement-style massive to semi-massive sulphide mineralization.
MAG's discovery in 2007 affirmed our conceptual model that continues to be refined and to inform our efforts in the exploration here and at our other CRD properties.
2007 & 2008: Drilling outlining large CRD system
A 12-hole, 6,316 metre drill program was conducted in 2007 and results appeared to define a massive sulphide manto ("blanket") now referred to as the Jose Manto.
The highlight from this program of widely-spaced holes was Drill Hole 07-20 which intersected 6.8 metres (estimated true thickness) of galena and sphalerite-rich massive sulphides grading 254 grams per tonne (g/t) silver (7.4 ounces per ton (opt)., 6.4 % lead and 7.0% zinc. This included a compositionally distinct interval, 2.12 metres thick, grading 512 g/t (15.9 opt) silver, 12.15% lead and 13.10% zinc.
Drilling thus far in 2008 has not only returned new high grade silver/lead/zinc, but also appears to have greatly extended the Jose Manto footprint. Hole 08-32, a 600 metre step-out to the southeast along the projection of the Jose Manto Trend, returned 4.03 metres of 80 g/t (2.3 opt) silver, 2.54% lead and 2.85% zinc. This mineralization occurs at the same depth and in the same limestone unit as the Jose Manto, and two (2) rigs are currently drilling 50 metre offsets to find the axis of mineralization before attempting to link this intercept back to the main body of the Jose Manto.
A third drill rig is testing a variety of geophysical targets including those generated by a recently completed 88 line kilometre detailed gravity survey covering an area of 10 kilometres by 20 kilometres. This survey has identified a significant gravity anomaly coincident with the magnetic low associated with the Jose Manto. This anomaly is located between 650 and 750 metres to the southeast of the main drill area. A second area of interest is developing 3,500 metres to the northwest along the Jose Manto Trend and a third area is developing a few kilometres to the southwest where the gravity survey has detected other significant anomalies under alluvial cover.
Cinco de Mayo: Outlook
Results from recent drilling continue to return encouraging grades and widths suggesting the presence of a large CRD system of undetermined magnitude. Mineralization remains open in all directions, and drilling continues to define the axis of maximum thickness of the manto and trace it towards its source.
Despite the extensive alluvial cover and limited drilling, MAG has now cut significant mineralization within a laterally traceable low-angle structural host over more than eight (8) square kilometres. The mineralization shows composition, textures, zoning and grades remarkably similar to other large CRDs.
Related News Releases:
| January 20, 2009 | Mag Silver Reports More High Grade Silver / Lead / Zinc Mineralization At Cinco De Mayo | |
| December 10, 2008 | MAG Silver Intersects More High Grade Silver / Lead / Zinc Mineralization At Cinco De Mayo | |
| September 18, 2008 | MAG Silver Expands Silver / Lead / Zinc Mineralization At Cinco De Mayo | |
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