Sudbury, Ont. — With support from Anglo American Platinum, its joint-venture partner,
In addition to increasing the resource, PNWC intends to determine the extent of the mineralized system to depth and along strike, as well as estimate the amount of drilling that will be required to delineate it.
The current drilling campaign, budgeted at $2.5 million, is to be completed by the end of May, bringing the total number of holes drilled to 220. Data from these holes will be incorporated into a new mineral resource estimate that is expected to be completed in June. The estimate will be performed by Derry, Michener, Booth and Wahl Consultants.
Anglo American Platinum (Amplats) has earned a half-interest in the property to date by spending $4 million. The major can boost its stake to 60% by funding all exploration leading to the completion of a feasibility study. Another 5% can be acquired in return for financing the project to production.
The River Valley property is in Dana Twp. and also occupies a portion of Pardo Twp., about 20 km by road northwest of the village of River Valley.
In October 2001, PNWC tallied an in situ resource of 12.7 million tonnes averaging 1.04 grams palladium, 0.35 gram platinum and 0.07 gram gold per tonne, plus copper and nickel credits. The resource is divided between the Dana Lake and Lismer’s Ridge zones.
At Dana Lake, mineralization is divided among two targets. The South zone has been traced for 300 metres and to a depth of 290 metres, whereas the North is known to extend 500 metres along strike and to a depth of 200 metres.
Measured and indicated resources at Dana North are pegged at 5 million tonnes grading 0.36 gram platinum, 1.06 grams palladium and 0.04 grams rhodium and 0.07 gram gold per tonne, plus 0.02% nickel and 0.11% copper.
The South zone hosts a measured and indicated resource of 2.7 million tonnes grading 0.39 gram platinum, 1.33 grams palladium, 0.04 gram rhodium, 0.07 gram gold, 0.02% nickel and 0.11% copper.
Mineralization at Lismer’s Ridge is similar to that found at Dana Lake but lower in grade. The former is 2 km southeast of the latter has been traced over a strike length of 500 metres.
Measured and indicated resources at Lismer’s Ridge are pegged at 4.4 million tonnes grading 0.32 gram platinum, 0.86 gram palladium, 0.06 gram gold, 0.02% nickel and 0.09% copper. Only mineralized intervals carrying more than 0.7 gram combined platinum and palladium were considered in the resource estimate.
Both zones remain open, and another 10 showings are known to occur elsewhere along the intrusion’s contact with surrounding country rock. PNWC is looking to expand its resource base in the Pardo zone, north of Dana Lake North, as well as in the 300-metre gap between Dana North and South. The junior will also target the area between Lismer’s Ridge and the newly discovered Banshee Lake zone, as well as the MacDonald zone, just south of Lismer’s Ridge.
Banshee Lake represents an induced-polarization (IP) anomaly measuring 600 metres long and up to 200 metres wide. which lies 300 metres south of the Dana Lake South zone and 1 km west of Lismer’s Ridge. The anomaly represents a faulted offset block from the main mineralized breccia unit. Seven holes have been drilled into Banshee Lake, and results are pending.
If the assays continue to expand mineralization, PNWC will add a third rig to the program and recommend that drilling be significantly expanded at a cost of an additional $3.5 million.
Geology
The River Valley property covers most of the northern contact of the River Valley intrusion and all of a northern offshoot of the main body. It represents a large, layered mafic intrusive complex that covers more than 100 km and consists of pyroxenite, melagabbro, gabbro and leucogabbro with minor anorthosite, gabbronorite and troctolite. Most of the known mineralization occurs as disseminated and bleb sulphides (mainly chalcopyrite) hosted in breccias and pegmatitic breccia zones along the margin of the intrusion.
Although River Valley is classified as a “contact-type” deposit, the mineralization exhibits features similar to the low-sulphide style of platinum group metals deposits.
“The magma that fed the intrusion was probably fertile in platinum group metals [PGMs] and already sulphide-saturated when introduced into its final resting place,” said Scott Jobin-Bevans, project geologist for PNWC, who spoke with The Northern Miner on a recent site visit. “At River Valley we see little evidence of crustal assimilation. There are no fragments of country rock. It’s all mainly gabrro and melanogabbro breccia, and there is no evidence of migration of PGMs into the surrounding footwall gneisses.”
Jobin-Bevans believes the magma welled up from a deeper chamber that was already PGM-enriched and that, once in contact with the cooler country rock, it precipitated PGMs and plated them along the contact of the intrusion. “As the magma slowly solidifies and acquires a toothpaste-like viscosity, it starts to slump and causes auto-brecciation,” explained Jobin-Bevans. “And as this breccia material mixes with new magma, more PGMs are scavenged and enrich the deposit.”
PNWC has subdivided the contact rock stratigraphy into units. Starting from the footwall gneissic rocks and moving into the intrusion, these are: footwall breccia; boundary zone; breccia unit; inclusion-bearing unit; and layered unit. The highest-grade mineralization is found in the breccia unit. The average distance from the footwall unit to the end of the Breccia unit is 100 metres.
Metallurgy
Platinum and palladium mineralization is hosted in tellurides and arsenides, such as sperrylite and merenskyite. Grains are typically 10-20 micrometres in diameter.
Preliminary metallurgical work by Amplats determined metal recoveries of 77% palladium and 73% platinum. Amplats took 13 composite samples weighing 4 kg each and ground them to the point where 60% of the material passed through 74 micrometres. All the mineral grains are less than 0.02 millimetres, and 80% of the grains are associated with silicate minerals, with the other 20% associated with the sulphides.
The metallurgical results show that the silicate magma had a lot of free PGMs in it and that there was a significant amount of localized re-mobilization, said Jobin-Bevans.
In addition to Amplats’ work, a graduate student performed a metallurgical study on 4,264 lbs. of rock from blast pits at the Dana North and South zones. At minus 100 mesh, where 80% of the material passed through 117 micrometres, metal recoveries returned 74.1% palladium, 68.5% platinum, 22.5% rhodium, and 73.4% gold.
History
The earliest recorded work on the property was performed in 1969 by Kennecott Explorations, then known as Kennco Explorations. Kennco was looking for copper-nickel deposits, and after taking some samples that yielded only low grade copper-nickel values, it dropped the property.
In 1973, the Ontario government withdrew 110 townships from staking as part of a staking ban in the Temagami Lake area. The area included part of the River Valley claims. When Michael Harris was elected premier in 1996, he renegotiated the land claims and opened 70% of the ground to staking, which subsequently led to the one of the largest staking rushes in the province.
In 1998, Lorne Luhta, previously employed with the Ministry of Mines, re-sampled an old Kennco pit. Assay results returned values in excess of 12 grams combined PGMs. Luhta and his two partners then approached PNWC and inked a deal.
In January 1999, PNWC optioned the property to Anglo Platinum, and, in July of that year, surface exploration began. The first exploration program consisted of geological mapping, prospecting sampling and IP geophysics. In January 2000, the junior performed a regional IP survey and kicked off its first phase of drilling, which consisted of 13 holes, or 2,000 metres.
The phase-2 program, which began in
May 2000, added 14 holes, or 2,820 metres, to the database. Subsequently, 111 holes were drilled. In total, PNWC has drilled 138 holes, or 22,807 metres, at River Valley.
The junior recently tabled more assay results from a 20,000-metre drill program at the Dana South and Lismer’s Ridge zones.
Two rigs are currently operating, and 38 of 80 planned holes have been completed to date. Holes DL-64, -65, -66, -67 and -68 were collared on 25-metre spacings that extended southeast from the Dana Lake South zone. Hole DL-68 lies only 150 metres north of the northern edge of the 600-metre-long Banshee Lake geophysical anomaly.
Results of the five holes drilled at Dana Lake South are as follows:
– Hole 64 intersected 101 metres grading 0.33 gram platinum, 1.07 grams palladium and 0.06 gram gold per tonne starting at a down-hole depth of 130.5 metres. Included was a 35.5-metre interval that assayed 0.59 gram platinum, 2 grams palladium and 0.1 gram gold per tonne starting at 195.5 metres down-hole, as well as a 2-metre, high-grade section that averaged 2.6 grams platinum, 8.1 grams palladium and 0.3 gram gold per tonne at a depth of 197.5 metres down-hole.
– Hole DL-66 intersected 104.5 metres grading 0.29 gram platinum, 0.85 gram palladium and 0.05 gram gold starting at 167.5 metres down-hole. This included a 7-metre interval that averaged 1.35 grams platinum, 4.33 grams palladium and 0.23 gram gold starting at 233.5 metres down-hole.
– Hole DL-68 cut 122 metres averaging 0.28 gram platinum, 0.78 gram palladium and 0.04 gram gold starting at 182 metres down-hole. This included a 10.5-metre interval that averaged 1.21 grams platinum, 3.79 grams palladium and 0.15 gram gold starting at 272.5 metres down-hole. Within this interval was a 1-metre high-grade section that returned 4.89 grams platinum, 10.32 grams palladium and 0.39 gram gold.
– Hole 65 was designed to determine the location of the footwall intrusive contact, as well as the extent of updip mineralization. It encountered footwall material over most of the hole and assayed anomalous PGM values, including 3 metres of 1.2 grams combined platinum, palladium and gold.
– Hole 67, also designed to test footwall contact, intersected only anomalous PGM values.
At Lismer’s Ridge, holes LR-45 to -49 were collared to infill a grid pattern to 25-by-50 metre spacings. Hole LR-46 was collared 1 km southeast of hole DL-68 at Dana Lake. Drilling at Lismer’s Ridge is gradually progressing southward on northeast-trending sections.
A rig is turning 600 metres north of previously reported hole LR-14 (45 metres grading 1.69 grams combined PGMs and gold).
Lismer’s Ridge results
Highlights of the infill holes at Lismer’s Ridge are as follows:
– Hole LR-45 intersected 16 metres grading 0.52 gram platinum, 1.13 grams palladium and 0.06 gram gold starting at a down-hole depth of 11.5 metres. This included a 2-metre section that averaged 1.5 grams platinum, 4.06 grams palladium and 0.16 gram gold.
– Hole LR-46 cut 4.5 metres grading 1.1 grams platinum, 2.97 grams platinum and 0.16 gram gold starting at 164 metres down-hole. Included was a 2-metre interval of 2.13 grams platinum, 5.81 grams palladium and 0.29 gram gold.
– Hole LR-47 hit 3.5 metres averaging 0.48 gram platinum, 0.84 gram palladium and 0.04 gram gold starting at a down-hole depth of 74.5 metres. This was followed by a 25.5-metre section that averaged 0.34 gram platinum, 0.89 gram palladium and 0.06 gram gold starting at 103 metres down-hole. The interval included 5 metres of 0.49 gram platinum, 1.47 grams palladium and 0.1 gram gold.
– Hole LR-48 cut 39.5 metres grading 0.27 gram platinum, 0.56 gram palladium and 0.04 gram gold starting at 173.5 metres down-hole. This included a 5-metre section that averaged 0.79 gram platinum, 1.44 grams palladium and 0.08 gram gold.
– Hole LR-49 cut 1 metre averaging 1.41 grams platinum, 2.44 grams palladium and 0.15 gram gold, starting at 94.5 metres down-hole. This was followed by a 16-metre interval that assayed 0.29 gram platinum, 0.58 gram palladium and 0.02 gram gold starting at 114 metres down-hole. Included in this interval was a 6.5-metre section that averaged 0.59 gram platinum, 1.19 grams palladium and 0.04 gram gold.
Recently, the company financed a private placement of up to 166,666 flow-through units priced at 60 each, for gross proceeds of $100,000. Each unit consists of one share and half a non-transferable warrant. A whole warrant entitles the holder to buy one additional share over three years at 60 each. At last report, PNWC had 22.7 million shares fully diluted.
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