Forum applies a century of experience to uranium hunt

Vancouver — Uranium exploration almost died with disco in the 1980s, resulting in a generation of geologists with little experience in this specialized niche. But with uranium a hot commodity once again, Forum Uranium (FDC-V, FDCFF-O) has the rare advantage of being able to apply 130 years of collective uranium experience to its hunt for new deposits in Canada.

President Rick Mazur says the company is focused on the search for new deposits in Saskatchewan’s Athabasca basin, the single largest uranium-producing region in the world with about one-third of global production, and the geologically similar but less developed Thelon basin in Nunavut.

Mazur has 13 years of uranium experience, as does project manager Bruce Harmeson, who was part of the Maurice Bay discovery team for Uranerz Exploration and Mining (UEM). Geophysical consultant Phil Robertshaw and chief geologist Boen Tan each have 35 years of uranium experience gained with UEM.

Tan is credited with the discovery of the 200-million-lb. Key Lake deposit, which changed the nature of uranium exploration in the basin. The main tool used in the early 1970s was radiometrics, which had limitations as unconformity-type deposits typically occur as very narrow linear lenses at considerable depth. These elongate bodies occur at or close to the unconformable contact between Athabasca sandstone and underlying meta-sedimentary basement rocks, often where basement faults intersect the unconformity. To make matters more challenging, the mineralization can extend significant distances above and below the unconformity, and may be structurally controlled.

In the case of Key Lake, Tan’s UEM team discovered uranium boulders and traced them for 5 km in an attempt to find an underlying deposit. Geophysical surveys revealed electromagnetic (EM) conductors, but these were initially attributed to the presence of nickel sulphides in the boulders.

“We didn’t know about graphitic conductors then, which later turned out to be the ‘key’ to the Key Lake discovery,” Tan says.

Graphitic rocks allow the creation of favourable structural settings necessary for the formation of unconformity-type deposits, and also are excellent EM conductors. Studying previously discovered deposits in the basin led to this understanding of their structural setting, which in turn triggered the discovery of the Key Lake deposit.

But as Tan points out, “there are lots of barren graphitic conductors in the basin,” hence the need for other modern tools and techniques such as deep-penetrating geophysical surveys and lake-sediment and other geochemical sampling methods to detect alteration and characteristic trace elements associated with unconformity-type deposits.

Forum applied its knowledge and expertise to assemble 1,600 sq. km of prospective ground in the Athabasca basin, with additional exposure through joint ventures with other companies active in the region. Forum also holds a 50% operating interest in a joint venture with Superior Diamonds (SUP-V, SUPYF-O) covering more than 1,000 sq. km in the Thelon basin of Nunavut.

Forum assembled the Saskat- chewan land package in 2004, but rather than rush to drill historic targets, the team spent another two years doing old-fashioned field work, including prospecting, regional and detailed mapping, and geochemical and airborne geophysical surveys.

Forum is looking for shallow, basement-hosted deposits similar to Cameco’s (CCO-T, CCJ-N) Millennium and Eagle Point unconformity-style deposits, and has focused its efforts on road-accessible properties near existing or future mill facilities.

Key Lake Road

Forum has conducted most of its recent exploration at its wholly owned Key Lake Road project, which covers 1,115 sq. km about 20 km southwest of the Key Lake mine-mill complex. Key Lake was placed into production by UEM in 1983, and produced until 1997. The complex is now jointly owned by Cameco and Areva Resources (previously known as Cogema Resources), a subsidiary of French energy company Areva (ARVCF-O).

Forum’s claims cover favourable basement rocks within the Mudjatik-Wollaston Tectonic Transition Zone, a 700-km-long, northeast-trending structural zone on the eastern rim of the basin that hosts all of the producing uranium mines and 95% of the known uranium deposits in Canada. The bulk of production comes from high-grade underground mines with grades of about 20% U3O8 (compared with the global average of 0.24%), but a portion comes from lower-grade deposits that can be mined by open-pit methods.

Historic exploration at the Key Lake Road project includes limited surface trenching and shallow drilling of outcropping uranium showings and geophysical anomalies. Deeper exploration for structurally controlled uranium deposits within basement rocks was not undertaken before Forum acquired the property, which includes untested EM conductors suggestive of graphitic zones in Wollaston basement rocks.

Forum’s 2005 summer program resulted in the discovery of several new uranium showings within or proximal to the Key Lake Road shear zone, a major structural trend interpreted to be the southern extension of the structure hosting Cameco’s Millennium deposit.

More than 150 km of EM conductive trends were prospected during the 2006 field season, which also included detailed work on the DD and Rainbow zones. Forum planned to conduct at least 7,000 metres of drilling in 2006 and 2007, as a “first-pass” test of priority targets.

A total of 14 holes were drilled to test the DD and Rainbow zones, with DD returning a number of low-grade uranium intercepts with geological similarities to Cameco’s basement-hosted, unconformity-style Millennium deposit. Follow-up drilling is planned.

New targets

The 2006 program also revealed promising new targets, including the Hobo zone, discovered by follow-up prospecting of conductive horizons in the vicinity of lake-sediment anomalies in the Hobo Lake area. The surface mineralization at the Hobo zone was found in graphitic rocks, with grab samples grading up to 1.82% U3O8.

A recent airborne magnetic/electromagnetic survey over the Hobo zone identified a 9 by 4-km feature interpreted as a synform of Wollaston metasediments overlying Archean basement rocks.

This survey outlined two concentric EM trends. A 5-km-long zone along one of the EM conductors is anomalous in surface uranium mineralization and lake-sediment geochemistry.

A program of follow-up ground geophysics is nearing completion and will be followed by a drill program.

Forum plans to test the Millison and Orchid Lake showings, and other widespread uranium occurrences in basement rocks along the Key Lake Road shear zone.

“We now have five or six good occurrences that warrant a look with a drill,” Mazur says.

Forum operates several properties through joint ventures. Forum, as operator, and 50% partner Hathor Exploration (hat-v, hthxf-o) have delineated more than 45 line-km of EM conductors on their Haultain River property, situated about 90 km southwest of the Key Lake uranium complex. The 101-sq.-km land package covers the same basement geological setting as known deposits in the basin.

The road-accessible property has historic EM conductors and surface showings. The partners plan to conduct follow-up exploration, including ground geophysics to refine priority drill targets.

Forum operates the Orchid Lake joint venture with Global Uranium (GU-V, GBAUF-O), situated 20 km west of the Key Lake complex. The property was staked by Forum based on a review of historical exploration data. In the 1970s and ’80s, UEM identified anomalous uranium in lake sediments near Orchard Lake, and then discovered pegmatitic boulders with narrow bands of graphitic gneiss grading up to 0.1% U3O8.

Recent geophysical surveys have identified two conductive trends that will be followed up by ground geophysics to define drill targets.

Forum holds a “strategically assembled” land package in the Thelon basin, which has many similarities to the A
thabasca basin, including the age and character of favourable host and basement rocks and structural features, and known occurrences of unconformity-type uranium mineralization.

The Thelon basin was explored in the 1970s and early ’80s with good success, until weak prices for uranium brought activities to a screeching halt. The region has since been revived by Areva, Cameco and others, with work focused on deposits with historic resources.

The land package held by Forum and partner Superior Diamonds is near the Kiggavik-Sissons project held by Areva, which hosts the largest known uranium resource in Nunavut. The claims also cover a portion of the structural zone hosting the Kiggavik-Sissons deposits.

Forum and Superior plan an aggressive exploration program, including airborne and ground geophysics, prospecting, geological mapping, and alteration studies of the Thelon sandstone in preparation for a drilling program.

— The author is a freelance writer based in Vancouver.