Big Nugget Gold Project
The Porcupine Creek gold field was discovered in 1898 by prospectors working as supply packers on the Dalton trail, an alternative route to the Klondike gold rush from the more famous Chilkoot and White passes. The Porcupine Creek area was the site of considerable placer mining activity between 1898 and 1936 with small operations still active in the area today, including placer mining on McKinley Creek.
The area is reported as one of the most important placer districts in southeastern Alaska. Minimum estimated production from sparse records through to 1985 are reported as approximately 80,000 ounces of gold. It was not until 1982 that surface discoveries by a local Haines prospector immediately upstream from the Porcupine placer operations provided a probable source area for the Porcupine placer gold. The gold prospects are well documented in historical government reports (Still, 1989 and Still et al.,1991).
From historical descriptions, the metasediments that host the gold prospects are described as dark gray, pyrite rich, micaceous, carbonaceous slate (“Porcupine slates”) with minor siltstone, limestone, and pebble conglomerate interbeds. The steeply dipping, east-west striking Porcupine slates are intruded by numerous altered mafic dykes that crosscut and follow the trend of the sediments. The altered mafic dykes range in thickness from a few feet to over 20 feet. The gold bearing samples from both the Golden Eagle and McKinley Creek Falls prospects are described as being mainly narrow discontinuous quartz veins (from a few inches to 2.0 feet thick) that occur most often as ladder style veins within the altered mafic dykes. The host silica-carbonate altered mafic dykes are reported to contain gold values up to 5.56 g/t gold and the gray to black Porcupine slates are reported to contain gold values up to 2.65 g/t gold.
Although the rocks cannot be correlated directly, the geological environment has some similarities with the AJ Mine in Juneau that yielded 3.5 million ounces of gold and 2.2 million ounces of silver from the late 1800’s until the mine closed in 1944. Surface and underground exploration at the AJ Mine by Echo Bay Mines Ltd. in the 1980’s established a geological inferred resource estimate of 100,000,000 tons with a grade of 0.04 ounces/ton gold (Redman et al, 1989).
The AJ Mine was characterized by narrow discontinuous quartz veins and stringers from a few inches to a foot or two in width and several tens of feet in length (Spencer, 1906) mainly in the dark slate/phyllites associated with highly altered, brownish mafic intrusives. Where the narrow quartz veins and stringers were sufficiently concentrated, they could be bulk mined from underground.
The information on the past producing AJ Mine and historical resource estimate as described in the U.S. government reports is provided as background information only. The AJ Mine is not located on the Company’s property and the information is not necessarily indicative of the mineralization on the Company’s property.
In August 2020, Constantine initiated an exploration program aimed at evaluating these previously untested areas of prospective high-grade gold mineralization. The surface geological work included evaluating the structural and stratigraphic setting of the gold mineralization and the distribution of altered mafic dykes which appear to be controls for the gold mineralization. A total of 143 rock samples and 566 soil samples were collected as part of the summer/fall program.
- Still, J.C. 1989: Bureau of Mines Mineral Investigations in the Juneau Mining District, Alaska, 1984-1988, Vol 2, Section A
- Still, J.C. et al.,1991: Economic Geology of Haines-Klukwan-Porcupine Area, Southeast Alaska, USBM
- Redman, E.C. et al, 1989: Bureau of Mines Mineral Investigations in the Juneau Mining District, Alaska, 1984-1988, Vol 2, Section D.