Mechanical Sorting Generates Encouraging Results at Karratha
VANCOUVER, British Columbia, Jan. 31, 2019 (GLOBE NEWSWIRE) -- Novo Resources Corp. (“Novo” or the “Company”) (TSX-V: NVO; OTCQX: NSRPF) is pleased to announce it has received encouraging results from initial testing of mechanical rock sorting of gold-bearing conglomerate from its Karratha gold project.
As discussed in the Company’s news releases dated November 19 and December 20, 2018, the potential viability of mechanical rock sorting was tested by subjecting four bulk samples (see Figure 1 below for sample locations) to crushing, screening, and sorting using a TOMRA mechanical rock sorter. Sorted rock concentrates of very small volume were generated returning high gold contents.
Assays of the sorted waste material, undersize (-6 mm) fraction and oversize fraction (+63 mm) have returned allowing for further evaluation of this technique (please refer to Table 1 below).
- Samples KX234 and KX237 generated 81.1% and 89.4% recovery of gold, respectively, from the 6-63 mm fraction that was sorted. These recoveries are considered very encouraging considering these tests are first pass and un-optimized. Interestingly, the best recovery is from the lowest grade sample, KX237.
- Although samples KX235 and KX236 generated lower recoveries, the fine (-6 mm) unsorted fraction of each of these samples displays higher grade than the respective calculated head grade. Novo believes the well-oxidized, crumbly nature of the rock comprising these bulk samples may have played a role in lower recoveries. Gold particles appear to have preferentially reported to the fines rather than remain encapsulated in rock that was sorted. Such oxidation persists to about 1-2 m below surface at Karratha. Below this level, Novo believes the targeted conglomerate will be harder and less crumbly.
- Sorter tailings commonly display gravity recoveries of gold of over 50% indicating significant coarse gold remains in this material. Novo believes crushing to somewhat finer size, perhaps 50 mm, may improve sorter recoveries because X-rays will more readily penetrate smaller rock particles making it easier for the mechanical sorter to identify gold particles.
- Although testing was conducted on rock particles down to 6 mm size, further work is needed to determine the lowest range of particle size that can effectively be sorted. Further crush testing is also required in order to determine means of minimizing generation of fines and maximizing the fraction of material that can be sorted.
- Gravity recoveries of gold from the undersize (-6 mm) fraction of the four bulk samples tested during this study range between 44%-64%. This data suggests gravity recovery of gold from unsorted fines may be a viable treatment option.
- Novo considers mechanical sorting a potentially low cost means of concentrating gold that is particularly suitable for the nuggety conglomerates Novo is exploring in the Pilbara. Novo is currently undertaking a thorough review of recent mechanical sorting test data to determine means of optimizing crushing and sorting and what further testing is needed.
Table 1 – TOMRA mechanical rock sorting results from four Karratha bulk samples.
| Sample ID | Mass (kg) | Size Fraction | Size Fraction as % of Total Mass | Mass of Sorter Concentrate (kg) | Mass of Sorter Concentrate as % of Total Mass | Gold Grade of Sorter Concentrate (gpt) | Gold Grade of Unsorted Material (gpt) | Gold Grade of Sorter Tails (gpt) | Stage Recovery of Sorter (%) | Gold Distribution to Sorter Concentrate (%) | Calculated Head Grade of Sample (gpt) | |||
| KX234 | 5460 | greater than 63 mm | 2.3% | - | - | - | 5.18 | - | 2.97 | |||||
| 6 to 63 mm | 67.2% | 13.5 | 0.25% | 792.4 | - | 0.68 | 81.1% | 66.0% | ||||||
| less than 6 mm | 30.6% | - | - | - | 1.43 | - | ||||||||
| KX235 | 3981 | greater than 63 mm | 19.3% | - | - | - | 0.21 | - | 1.91 | |||||
| 6 to 63 mm | 64.8% | 19.1 | 0.48% | 188.8 | - | 1.01 | 58.1% | 47.5% | ||||||
| less than 6 mm | 15.8% | - | - | - | 1.95 | - | ||||||||
| KX236 | 4205 | greater than 63 mm | 9.6% | - | - | - | 0.57 | - | 1.40 | |||||
| 6 to 63 mm | 61.5% | 13.0 | 0.31% | 92.1 | - | 0.70 | 39.8% | 20.3% | ||||||
| less than 6 mm | 28.9% | - | - | - | 2.19 | - | ||||||||
| KX237 | 4418 | greater than 63 mm | 9.2% | - | - | - | 0.17 | - | 0.46 | |||||
| 10 to 63 mm | 41.5% | 3.2 | 0.07% | 377.8 | - | 0.08 | 89.4% | 60.3% | ||||||
| less than 10 mm | 49.3% | - | - | - | 0.27 | - | ||||||||
| Size fractions in italics were too coarse or too fine to be sorted | ||||||||||||||
| Reported masses may be slightly different to those quoted in the Company's news release dated December 20, 2018 because materials were re-weighed at the assay laboratory | ||||||||||||||
"Novo is highly encouraged by initial mechanical sorting results,” commented Rob Humphryson, CEO and a Director of Novo. “Typically, mechanical sorting machines are utilized to upgrade mineralization by sorting out waste. In this case, gold is being directly and effectively concentrated. Novo expects that optimizations can be made to further enhance this means of gold recovery."
Novo staff collected bulk samples discussed in this news release. Bulk samples were crushed at Cook Industrial Minerals in Perth, Australia prior to being shipped to TOMRA. Once rock sorting was completed, the concentrate and smaller mass tailings samples were submitted to MinAnalytical Laboratory Services Australia in Perth, Australia for analysis via Photon assay and fire assay. PhotonAssay methodologies are described in Novo’s news release dated December 20, 2018. Larger tailings samples were submitted to SGS Minerals in Perth, Australia where they were treated in a test plant detailed in Novo’s news releases dated February 6 and May 31, 2018. All assay certificates and head grade calculations were provided by SGS and MinAnalytical, with the calculations and head grades checked by Novo internal resources. There were no limitations to the verification process and all relevant data provided to date was verified.
Dr. Quinton Hennigh, P. Geo., the Company’s, President, Chairman, Director, and a qualified person as defined by National Instrument 43-101, has approved the geological content of this news release.
About Novo Resources Corp.
Novo’s focus is to explore and develop gold projects in the Pilbara region of Western Australia, and Novo has built up a significant land package covering approximately 12,000 sq km with varying ownership interests. For more information, please contact Leo Karabelas at (416) 543-3120 or e-mail
On Behalf of the Board of Directors,
Novo Resources Corp.
“Quinton Hennigh”
Quinton Hennigh
President and Chairman
Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this news release.
Forward-looking information
Some statements in this news release contain forward-looking information (within the meaning of Canadian securities legislation) including, without limitation, statements as to planned exploration activities and the expected timing of the receipt of results. These statements address future events and conditions and, as such, involve known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the statements. Such factors include, without limitation, customary risks of the mineral resource industry as well as the performance of services by third parties.
Figure 1 – Plan map showing the location of samples KX234, KX235, KX236 and KX237. Sample KX234 is material from the Lower Cannonball Conglomerate. The remaining samples are from the Upper Cannonball Conglomerate.
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