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CSL.V Stock Symbol

Corona


Corona Location Map
Click here to enlarge


 
 
 
 
 
 
Esperanza Drill Hole Plan
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The Corona project (1370  hectares) is approximately 270 km southwest of the city of Chihuahua, Mexico. Comstock Metals Ltd. holds an option to earn up to a 75% interest in the Corona Property pursuant to an earn-in agreement

The property is located in the Sierra Madre Occidental precious metal belt, hosting producing gold-silver mines such as Ocampo, Dolores, Pinos Altos, El Sauzal, and Mulatos.

Mineralization on the Corona property was first discovered approximately 300 years ago, and small mining concessions were centered on the mineral showings at Esperanza, La Mula, and Alcaparra. Exploration during the period from 2001 to 2003 was the only modern work completed and included mapping, sampling, geophysics, and 6,500 metres of Reverse Circulation (RC) drilling in 59 holes.

The Company has completed an NI 43-101 report on the Corona Gold-Silver Project based on geological mapping, rock, soil and stream sediment sampling, and geophysics.  In February and March 2012, the company completed a diamond-drilling program of twelve holes (2,126 metres), which discovered two new zones, one of porphyry-style gold mineralization after drilling 34.5metres of 0.36 g/t gold and the second is Esperanza high grade gold-silver vein assaying 258 g/t Ag, 6.33 g/t Au, 3.8 % Pb and 2.83% Zn over 1.00 m.  See May 8th news release for more information.

Esperanza Vein

The Esperanza Showing is exposed in an old adit dug into an overburden covered hillside, mineralization consists of a coarsely banded quartz vein that is up to 30 cm wide hosted within sericite-altered and silicified diorite. Zinc and lead minerals are evident as sphalerite and galena. Grab samples taken in 2002 and 2007 from the adit returned assays of 12.43 g/t Au, 2,634 g/t Ag, 8.35% Pb, 3.84% Cu and 3.84% Zn (Golden Goliath Resources) and up to 42.6 g/t Au and 76.4g/t Ag across 15 cm from in-house sampling.

The Esperanza showing itself may be part of a larger east-west trending set of structures that returned high gold and silver values in earlier programmes. Approximately 1000 metres west is the Cerro el Cruz prospect, reportedly of similar mineral-style, and 200 to 300 metres to the east highly anomalous rock and soil samples have been collected, some returning gold values exceeding 14,000 ppb. Further work is required within this prospective corridor, as well as towards the Northeast Zone, which will hopefully lead to a unified exploration model and more drilling. Click here to see the 2012 Esperanza drill hole plan.


The Esperanza Zone is similar target to the Santo Nino Vein (Fresnillo) where 1st drill hole at 300 m depth drilled 1.6 g/t Au, 1087 g/t Ag, 0.4% Pb, 0.7% Zn/3 m. Santo Nino Vein dimensions are 2.5 km long x 500 m deep x 2 m wide.

 


Geological Map and Targets
Click here to enlarge.

 

A New Example of High Sulphidation Epithermal Gold Mineralization in Northern Mexico

The Corona Property is underlain by Tertiary-aged volcanic and intrusive rocks (Figure 1) broadly subdivided into the “Upper Volcanic Group” (predominately rhyolite tuff, ignimbrite and flow with variable thicknesses of red-coloured conglomerate and sandstone)) and the “Lower Volcanic Group” (mostly andesite plus sedimentary rocks). This two-fold subdivision is in widespread usage in north-western Mexico, where many of the region’s precious and base metal deposits are found in the Lower Group and the Upper Group acts as a cover, concealing mineralization. Several significant deposits are the same age or occur in the Upper Volcanic sequence such as El Sauzal (Goldcorp), Mulatos (Alamos Gold) and a very recent discovery, the Orisyvo gold deposit (Fresnillo PLC), which reported to have indicated & inferred resources of 2.72 million ounces of gold in oxides and 6.51 million ounces of gold in sulphides.

Recent core drilling and geological mapping has shown that the gold-silver mineralization at Corona is also “High Sulphidation Epithermal” in origin. At Corona prospecting and mapping has found an area known as the “Jerry Zone” where the rhyolite flows and tuffs of the Upper Group are highly fractured, brecciated and altered to an alunite-rich rock that passes into outcrops of leached rhyolite with extensive and well-developed vuggy and residual silica. Between the areas of near-massive vuggy quartz the host rock is highly fractured and has spectacular networks of dark vuggy silica veinlets and silica-cemented hydrothermal breccia (Plates 1 to 3). The zone of vuggy silica has been traced in outcrop and float over a distance of 800 metres. At the northern end of the zone extensive areas of alunite alteration occur within pumice and tuff (Plate 4) that is in fault-contact with the Jerry Zone. The mineralogy, occurrence and trace element geochemistry suggests that the Jerry Zone is the high-level “lithocap” of a concealed mineral system.

Drilling during February and March 2012 started on the “Northeast Zone”, 250 to 300 metres east of Jerry. Here mineralization is focused along the contact between the Upper and Lower Volcanic Groups as zones of advanced argillic alteration marked by pyrophyllite, sericite and hematite. Similar mineralization is present in the NE Extension, up to 500 metres to the southeast. This mineralization is also part of a high sulphidation system. Comstock’s 2012 drilling started testing a portion of the area between the NE Extension and the southern end of Jerry with some relatively shallow drill holes (CO12 – 64 to 67), resulting in the discovery of extensive thicknesses of highly fractured granodiorite, diorite, and hydrothermal breccia that is densely fractured and often well-mineralized. This “porphyry-style” gold mineralization is oxidized, with pervasive hematite, and silicification plus “clay” alteration that is locally intense, but pyrite is rare or absent (Plate 5 to 7).

It appears that drilling beneath the lithocap and extending into un-drilled terrain north and south may define an intrusive body forms a “cupola” or dome of highly fractured and brecciated porphyry that may extend well beyond the areas of both current and historic drilling.

 

2012 Plans and Sections:

 2012 Drill Hole Plan Map

 2012 Drill Hole Assays: Please click here

 

2012 Core Photos:

 

 

 
 
     
CO-12-67
120m-122.7m
 
CO-12-67
122.7m-125.5m
 
CO-12-67
125.5m-128m
  CO-12-67
128m-130.7m
  CO-12-67
130.7m-133.5m
  CO-12-67
133.5m-135.5m
                     
         
CO-12-67
135.5m-138.5m
  CO-12-67
138.5m-141.5m
  CO-12-67
141.5-144m
  CO-12-67
144m-147m
  CO-12-67
147m-149.5m
  CO-12-67
149.5m-152.5m
                     
                 
CO-12-67
152.5m-155m
  CO-12-67
155m-156m
               

 

 


Sample Bulk-Tonnage Target RC Drill hole Intersections

Drill Hole (RC)

From (m)

To (m)

Width (m)

Gold (g/tonne)

CO-02-9

44.20

62.48

18.28

1.09

CO-02-18

50.29

74.68

24.39

1.55

CO-02-21

18.29

32.00

14.71

1.63

CO-02-23

18.31

38.15

19.84

1.21

CO-02-32

19.84

32.05

12.21

1.59

For the high-grade gold-silver vein type intersections, please click on the Corona Vein system map.

During 2007-2008, Comstock carried out additional stream sediment sampling and soil and rock geochemical surveys, detailed 1:1,000 scale geological mapping conceptualizing a geological model for the Corona Property, and completed a NI 43-101 Technical Report in preparation for a diamond drill program.

 

Highlights of 2008 Work

The 2008 chip-sampling program returned the following assays:

  • 8.77 g/t gold over 5 m (true width) at a previously untested area of Alcappara zone,
  • 814 g/t silver over 8 m (true width) south of Northeast Zone,
  • 114g/t silver, 2.28% Cu and 0.2 g/t gold over 10 m (true width) in a new zone south west of La Mula,
  • 22.25 g/t gold, 667.5 g/t silver, & 16.3% Pb over 0.5 m in the Esperanza zone.

       

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