The mining newspaper for Alaska and Canada's North
The mining newspaper for Alaska and Canada's North
Ocean Park geologists find 126.5 g/t gold, 17.7 percent copper and 681 g/t silver across a 12-km trend at Chisna in eastern Alaska
Ocean Park Venture Corp.'s 2011 exploration at the Chisna project in eastern Alaska has revealed Golden Range, a district-scale iron-carbonate zone rich in gold, copper and silver. Grab samples from this iron-carbonate zone that has now been traced for more than 12 kilometers (7.5 miles) have returned assays as high as 126.5 grams per metric ton gold and 17.7 percent copper; and one drill intercept averaging 681 g/t silver over 2.7 meters.
Optioning the Chisna property from Corvus Gold Inc. (International Tower Hill Mines Ltd.) late in 2009, Ocean Park launched a C$6.2 million exploration program in 2010 focused on Grubstake, a porphyry copper-gold target located on the southeast end of the Chisna land.
"The drilling (at Grubstake) was not of strong immediate interest. There were locally good gold-mineralized structures that cut that porphyry system, but it wasn't the type of target that we felt we wanted to put more drilling into at the moment," Ocean Park Vice President of Exploration Chris Taylor told Mining News.
Although the 5,000-meter drill program carried out in 2010 failed to tap the economically viable mineralization targeted, a reconnaissance team led by Ocean Park geologist Nadia Caira turned up a number of other promising targets across the 914-square-kilometer (353-square-mile) property. The most intriguing of these was Golden Range.
"We like what we see at the Golden Range so much that my preference is to keep the drills focused there," Taylor explained in September. "This year we plan to demonstrate that we have a very interesting, very significant gold-bearing system present on that target."
Notch, the gold-bearing system of which Taylor spoke, was one of four gold-silver prospects that Ocean Park targeted with its 2,800-meter late season drill program.
Testing Notch
In early November the junior released the first round of drill and trench results from its 2011 exploration program at Golden Range.
Six drill holes and four surface trenches were completed at the Notch target to test a 50-meter-thick shear zone that has been mapped for 1,000 meters along strike and remains open to the west.
"The combination of the drilling and trenching at Notch was the main focus of the work we did this year," Taylor told Mining News Jan. 17.
This structural zone was targeted as two similar but separate areas, Notch East and Notch West, divided by a talus slope with no bedrock exposure.
Hole GR-11-09, drilled at East Notch, cut 6.8 meters averaging 4.49 grams per metric ton gold within a 15.8-meter intercept that averages 3.19 g/t gold and 1.93 g/t silver;
GR-11-015, also drilled at East Notch, cut 5.1 meters averaging 4.57 g/t gold within a 16.9-meter intercept grading 1.99 g/t gold; and
GR-11-13 returned 44.9 meters of 0.34 g/t gold and 0.68 g/t silver. GR-11-14 returned 0.4 g/t gold over 37.5 meters.
Ocean Park said surface trench results are of similar tenor to drill intercepts.
Trench EN-TR-01, dug at East Notch, revealed 47 meters averaging 1.01 g/t gold and 1.27 g/t silver.
Trench EN-TR-03, also at East Notch, revealed 5 meters of 13.21 g/t gold and 6.09 g/t silver within an 11-meter intercept averaging 6.48 g/t gold and 3.2 g/t silver.
Combined, the drill and trench results suggest good continuity of mineralization from surface to more than 250 meters down dip. Higher grade gold mineralization is concentrated in more strongly altered intervals within the regional shear zone.
The results of the 2011 exploration indicate the two zones are both part of the same gold-mineralized structure that stretches for at least 1,000 meters along strike.
Notch will be a target of definition drilling when Ocean Park returns to the property in 2012.
Green Zone
While Notch is an exciting target for the upcoming drill season, the Green zone may be the most exciting discovery of the 2011 exploration program at Golden Range.
Earning its name from the extensive copper staining that led geologists to the prospect, the Green zone was a late season discovery.
"When we finished off the work for the season we started working in what would be the current northwest extent of the Golden Range and we found this really high-grade copper-silver-gold mineralization sitting there," Taylor explained.
Highlights from the Green zone sampling program include:
H271989 averaged 126.5 g/t gold, 129 g/t silver and 0.4 percent copper;
H262393 averaged 28.2 g/t gold, 198 g/t silver and 5.1 percent copper; and
H262397 averaged 3 g/t gold, 144 g/t silver and 17.7 percent copper.
Of the 29 grab samples collected from this high-grade gold-silver-copper discovery, 16 returned assays topping 1 g/t gold; 90 percent returned assays of more than 0.1 percent copper; and most also contain high-grade silver.
While some of the geologists that worked at the Green zone believe it has porphyry association, Taylor is reserving judgment until the zone is more thoroughly investigated.
Defined by strong copper-iron gossans, geologists were able to map the Green zone for about 300 meters along strike before winter weather ended the 2012 exploration. Ocean Park said it plans to continue the mapping and geochemical testing of this high-grade copper-gold-silver prospect in advance of a drill program slated for 2012.
More targets
City, Matador and Corazon were three additional Golden Range prospects Ocean Park investigated with trenching and drilling in 2011. The company said the veined quartz-arsenopyrite mineralization found in these zones is consistent to what it encountered at Notch.
Highlights from these Golden Range zones include:
Hole GR-11-08, drilled at Matador, encountered 2.7 meters grading 681 g/t silver;
Trench CZ-TR-01, excavated at Corazon, cut 7.5 meters averaging 3.3 g/t gold and 4.6 g/t silver; and
Hole GR-11-01, drilled at City, returned 0.7 meters of 6.2 g/t gold and 6.7 g/t silver.
"The 2011 exploration results from the Golden Range target area have highlighted a new and significant district scale gold discovery with numerous high-grade gold and silver targets which have returned encouraging results.
In addition, the continuity and intensity of the surface soil and rock mineralization at Golden Range is very encouraging for the presence of a major precious metal deposit," Corvus CEO Jeff Pontius commented on Ocean Park's 2011 discoveries.
"The continued porphyry association for mineralization in the belt, such as the recent Jolly Green discovery, continues to offer significant potential for new copper-gold discoveries as well.
We at Corvus look forward to our partner's further work on this exciting new Alaskan gold discovery."
Ocean Park can earn an initial 51 percent interest in Chisna from Corvus by spending US$20 million on exploration by 2015. It can increase its stake in the expansive property to 70 percent by completing a positive feasibility study within 5 years of the initial earn-in.
Though final numbers are still being calculated, Ocean Park spent around US$3.5 million on 2011 exploration at Chisna. Combined with its 2010 work, the junior has spent about US$9.7 million, or about half its initial earn-in.
The Ocean Park Board of Directors have yet to outline the size and scope of the 2012 program, but Taylor, who does not sit on the board, believes the upcoming program will focus on expanding Notch and investigating the exciting copper-silver-gold discovery made at Notch.
"Because we have this high-grade polymetallic mineralization at the Green Zone, I believe the board will see that as a highly attractive target, and they will want to follow up on that and the drilling we did at Notch, those were very nice preliminary results," Taylor said.
"If I had to anticipate what we are going to be doing next year (2012 season), I would say it's going to be follow-up drilling on the Notch and the Green zone - the other targets probably as time permits," the exploration VP added.
Over his more than 16 years of covering mining and mineral exploration, Shane has become renowned for his ability to report on the sector in a way that is technically sound enough to inform industry insiders while being easy to understand by a wider audience.
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