VANCOUVER — Novo Resources (TSXV: NVO; US-OTC: NSRPF) is “uncomfortable” with the experimental, bulk-sampling technique it has been using for grade estimation at the company’s Purdy’s Reward paleoplacer joint-venture gold project with Artemis Resources (ASX: ARV) in Western Australia.
Novo said in a Nov. 24 press release that after “careful review of sample consistency, integrity and recovery” the company intends to review other options for collecting bulk samples from drilling.
“While the ability to recover consistent, quality sample material using large-diameter drilling has not yet been accomplished, trenching appears to yield acceptable bulk samples for test work. Bulk sampling at surface will be the most critical means of determining the grade, processing characteristics and viability of this deposit,” Novo chairman and president Quinton Hennigh, president of Novo, said in the press release.
The company also revealed that the fine-grained gold within the deposit occurs as halos around coarser gold nuggets, having been freed by higher pressures and temperatures during low-grade metamorphism.
Looking south at the Comet Well area, part of Novo Resources’ Karratha gold property in Western Australia. Weathered, gold-bearing conglomerates occupy the foreground and liberated quartz cobbles are scattered across the surface. Credit: Novo Resources.
If the fine-grained gold had been disseminated throughout the host rock, it would have proved helpful in evaluating the grade and continuity of the deposit, the company said in an earlier press release.
The news drove Novo shares down 18%, or $1.20, to $5.45 at press time, whereas shares of Artemis were steady, up A3¢ to A38¢ per share.
A liberated “watermelon seed” type gold nugget from the Comet Well area. The blue lines are 1 mm apart. Credit: Novo Resources.
Novo has completed 60 diamond drill holes on a 50-metre grid within a corridor measuring 1,000 metres long and between 100 and 400 metres wide at Purdy’s Reward, which is part of its much larger 7,600 sq. km Karratha gold project.
At least 12 of the holes across a 400- by 200-metre area have hit the target horizon — a 4- to 20-metre-thick package of conglomerates sandwiched between the greater than 3-billion-year-old Pilbara craton and the 2.8-billion-year-old Mt. Roe basalts.
Once target depth and thickness have been determined, the company plans to drill large-diameter percussion holes measuring 17.5 inches to collect bulk samples.
Results from the rest of diamond drilling and surface trench work have yet to be released, and plans are underway to finish a 20,000-tonne bulk sample.
Geological Model
Finding gold nuggets in Novo’s first bulk sample in July drove shares of the company up 925% to an $8.55 peak on Oct. 10.
Hartwig Frimmel
But how the gold was emplaced within the conglomerates is a mystery to most gold investors, many of whom have coined the deposit as a “Wits 2.0” after South Africa’s 1.5 billion oz. paleoplacer gold Witwatersrand deposit.
However, an interview with Wits geology expert Hartwig Frimmel, appearing in The Northern Miner’s podcast “Episode 77: What’s up with the Witwatersrand?” outlined three main differences between the paleoplacer gold in Western Australia and the gold found in the Wits: the age, the nature of gold and preservation of the host.
Frimmel said the mature sedimentary basin hosting paleoplacer gold at Wits is “perfectly preserved,” being 5 km thick and capped by 2.7-billion-year-old basalt flows. In Karratha, placer gold is found within a thin package of immature conglomerates, sitting above a major unconformity and below basalt flows of a similar age.
He also noted that the gold at Wits is “micron-sized,” with the richest parts found within 2.9-billion-year-old strata, whereas the gold in Karratha is nuggety and found within younger rocks.
Examples of in situ gold nuggets frozen in matrix material from the Comet Well and Purdy’s Reward area at the Karratha gold project in Australia. Credit: Novo Resources.
In an updated presentation, Novo has confirmed that the Comet Well-Purdy’s Reward deposit is a “near-shore marine alluvial gold deposit” similar to the “gravel lag deposits” in Nome, AK, where gold-bearing gravels underlie tens of square kilometres of the Bering Sea.
At Nome, what is now the Bering Sea was once above sea level and served as a land bridge between two continents. When it rifted open, gold-bearing rivers washed into the ocean for millions of years. Storm wave action, coupled with the rise and fall of sea level, concentrated gold along the beaches, which is why the nuggety gold is found at its shallower margins.
Radio carbon dating is extrapolation beyond reality. It is false.
I didn’t know “uncomfortable” was a term recognized by CIMM, or NI 43-101 for disclosures.