La Mina Porphyry Gold Copper Project, Colombia

 

La Mina is a resource stage porphyry gold-copper project located in the Middle Cauca volcano-plutonic belt in the Department of Antioquia about 45 km southwest of Medellin. The Middle Cauca belt is known to host large porphyry gold deposits such as AngloGold's La Colosa Deposit and Sunward Resources' Titiribi Project.

 



The property is accessible by paved and improved dirt roads. The core project area is located between 1,600m and 2,000m elevation with power, water, and labor readily available.



 

As of July 9, 2012, the La Mina Project encompasses inferred mineral resources totaling 1.6M oz of gold and 419M lbs of copper summarized below:

 

 

*Gold equivalent grades have been calculated using the following formula:  AuEq = Au(g/t) + [Cu(%)} x {%Recoverable Cu / %Recoverable Au} x {Net Cu Price/Net Au Price} x {%Payable Cu / %Payable Au x 22.0462 x 31.1035].  Metal recoveries are estimates based on metallurgical results announced in Bellhaven’s news release dated Nov. 15, 2011.  Net metal prices for gold and copper are the long-term forward-curve metal price minus refining charge. Metal prices based on the long-term forward curve are as of May 8, 2013 (US$1482 for gold and $3.40/lb for copper).  Metal refinery charges and % payable metal by the smelter are estimates based on third-party consultants.  Metal prices, refinery charges and % payable metal are not constant and are subject to change. Mineral resources are not mineral reserves and do not have demonstrated economic viability.  There is no certainty that all or any part of the mineral resources will be converted into mineral reserves.

 

The information shown on this site, has been prepared under the supervision of Mr. Thomas J. Drown, P. Geo. Mr. Drown has more than 25 years relevant experience and is a British Colombia Professional Geoscientist. He is a senior project geologist with the Company at the La Mina Project and serves as the qualified person as defined by National Instrument 43-101

 

Project History


 

The La Mina concession has been the subject of modern era exploration since approximately 2002. Bellhaven and its predecessor companies have conducted: geologic mapping, airborne and ground geophysics, stream sediment, rock, and soil sampling, trenching, and diamond core drilling. A joint venture between AngloGold Ashanti and Bema Gold (later B2Gold) drilled six holes into the La Cantera porphyry in mid-2006. After identifying the La Cantera deposit in drill holes and highlighting numerous other targets, the AngloGold – B2 Gold joint venture dropped the concession that would later become Bellhaven’s La Mina Project. After acquiring the mineral rights in mid-2010, Bellhaven has delineated mineral resources* on both the La Cantera and Middle Zone porphyry complexes. Bellhaven drilling in 2011 and 2012 discovered the La Garrucha and El Limon porphyry centers, but these targets are still at the resource definition stage.


Exploration Targets


 

The La Mina concession includes almost 2,000 hectares. A number of anomalous features are evident from the initial airborne magnetic survey, completed by AngloGold. As surface sampling and drilling progressed, a number of multi-faceted targets emerged. Through the first half of 2012, a total of four known mineralized porphyry systems have been identified; two of these deposits are host to inferred mineral resources*. The two remaining known porphyries will be the focus of future drilling, meant to advance these prospects to the resource stage as well. The exploration pipeline at La Mina includes a number of other targets that, based on geology, geochemistry and geophysics, have characteristics similar to porphyry or porphyry related deposits. There are at least 7 of these discrete targets undergoing additional work, but they have not yet been drilled. The figure below shows total magnetic intensity (reduced to pole) from an airborne magnetics survey. Many of the targets are identified on this map; and more detailed information is available below.

 

 

 

At the deposit scale, most gold and copper discovered thus far is spatially associated with complex veining, brecciation, and/or disseminated sulfide minerals in potassically altered porphyry and related breccias. The dominant types of veining on the La Mina Project include: quartz+pyrite+chalcopyrite (and lesser bornite); quartz-magnetite; magnetite; gypsum/anhydrite; and/or calcite (+ sphalerite, pyrite, stibnite). An important gangue mineral that is highly correlative with gold and copper is hydrothermal magnetite. As a result, the gold-bearing rocks are highly magnetic.



 

La Cantera:
  AngloGold Ashanti/Bema Gold drilled six holes into the La Cantera porphyry target. Holes 2 and 5 yielding 90+ m intercepts of greater than 1 g/t Au and significant copper at shallow depths. Drill-holes 4 and 6 also contained significant values located near the surface.

 

In 2010, Bellhaven began advancing the exploration at La Cantera. Surface work including mapping, sampling, and ground magnetics helped refine the target and drilling started up again during the second half of 2010. The Company soon built on the good intercepts from AngloGold’s initial holes. The La Cantera deposits includes a late stage intrusive that does not host significant mineralization; but interestingly, much of the best grades for both Cu and Au occurs very near surface and along the flanks of that porphyry body. The La Cantera deposit has a relatively simple geometry; it is nearly vertical and round to oblong in plan view. The table below includes selected significant intercepts from drilling at La Cantera (See the Technical Report for complete descriptions of geology, drill results, and the mineral resources):

 

 

Driling on the La Cantera Deposit progressed through the middle of 2011, totaling 8,032 meters in 25 drill holes (including the AngloGold drilling). Bellhaven announced the maiden mineral resource on the La Cantera deposit in September of 2011. At that point, drilling had already identified significant porphyry style mineralization at the Middle Zone and at the El Limon target.

 

Middle Zone: The Middle Zone porphyry – breccia pipe complex crops out approximately 400m north of the La Cantera Deposit. Mapping, magnetics, and rock sampling identified the Middle Zone anomaly early in the project’s life, but AngloGold did not drill test the target. During the summer of 2010 trench samples yielding gold values of 0.7 g/t spawned the first drilling. The first Middle Zone drill results were reported in October of 2010 and included more than 60m of 0.5 g/t Au. The Middle Zone deposit is a bit more complex in shape and geology than La Cantera. The footprint of mineralization is approximately 450m long in the NE direction by 200 - 300m in the NW-SE direction. Here as well, the most gold-rich mineralization tends to occur shallower than 250m. The table below is a summary of selected intercepts from Middle Zone drilling.

 

 

Driling at the Middle Zone progressed through May of 2012, totaling 14,159 meters in 39 drill holes. Bellhaven announced an updated mineral resource, which included the Middle Zone, on July 9, 2012. The Middle Zone constitutes the second porphyry-breccia center on the La Mina Project to advance to the resource stage.

 

La Garrucha: Near the eastern edge of the property there is a pronounced magnetic high associated with anomalies in rocks and soil. Bellhaven geologists conducted some mapping in the area and after examination of the surface rocks have interpreted another porphyry center called the Garrucha porphyry. Surface anomalies included rock chip samples containing more than 0.7 g/t Au. Finally in very late 2011, the Company drilled 6 holes into the La Garrucha anomaly. Four of the six holes encountered significant mineralization, including 64m of 0.8 g/t Au Equivalent and 24m of 0.85 g/t Au Equivalent. Grade and thickness of the intercepts increased down hole and to the east, so the system is expected to strengthen in that direction. 



 

*As reported in the NI43-101 Technical Report entitled "Amended Technical Report of La Mina Gold-Copper Project" and dated May 2 2013

 

 


 

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