Rockcliff Metals Corp. Provides Results on Bur Project Metallurgical Testing
Sudbury, October 29, 2020 - Rockcliff Metals Corp. (CSE: RCLF) (FSE: RO0) (WKN: A2H60G) ("Rockcliff" or the "Company") is pleased to announce results from a metallurgical characterization study completed on the Bur Property. The results indicate that a selective separation of zinc and copper is feasible without the use of cyanide, and clean marketable concentrates can be made from the tested sample. Ore sorting was also successful in rejecting waste from the mineralized rock. Mr. Alistair Ross, President and CEO commented, "The characterization testing program has demonstrated a number of important positive factors. First, the mill chemistry regime currently being considered for Tower and Rail works well on the Bur sample. A relatively simple piping change to switch the copper and zinc circuits to account for the change in volume between the two metals is all that seems to be required. In addition, ore sorting has shown the ability to significantly upgrade the mined ore by rejecting the waste rock from the mined tonnage. Results of ore sorting indicate up to 25% mass rejection to a waste stream that will be placed underground. This will have a significant impact on reducing transportation costs to the mill, lowering milling costs by not having this waste material processed in the plant - and also reducing the tailing storage capacity by keeping this rock at the mine site. The mineralization adjacent to the Bur deposit has grown significantly in strike length and remains open in all directions. This is a very important as Rockcliff looks to add additional resources to the potential mine production pipeline."
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About the Bur Property
The Bur Property, located in the Snow Lake region of Manitoba is 100% owned by Rockcliff. The Bur Property is subject to a Hudbay Minerals Inc. ("Hudbay") back-in right. The back-in right gives Huday the ability to acquire a 70% ownership interest in the property by making cash payments to Rockcliff totalling $3,000,000 plus two times the amount of expenditures incurred by Rockcliff during the back-in waiting period to a maximum of $1,500,000. The back-in right expires on August 11,2021. If Hudbay does not exercise its back-in right, Rockcliff as the operator, shall pay Hudbay a 2% of Net Smelter Return Royalty from the date of the commencement of commercial production.
Metallurgical and Ore Sorting Update for Bur Deposits
Results generated from recent benchscale testing completed under the direction of Jake Lang at Base Metallurgical Laboratories in Kamloops, BC ("BaseMet") has identified and confirmed a selective flowsheet to produce separate copper and zinc concentrates while achieving industry accepted market quality. The treatment process is similar to that previously reported for Tower, Rail and Talbot; conventional by which copper and zinc are recovered sequentially by flotation requiring a relatively coarse primary grind of 115 micron k80 and regrind sizes in the 25 to 30 micron k80 for both copper and zinc. The flowsheet tested does not require the use of cyanide to separate zinc from copper and the reagent scheme is applicable to all four properties based on the samples tested. Testing was completed on selected drill hole samples attempting to characterize the orebody. Results produced from open circuit batch tests are described in the following table showing concentrate quality and metal recoveries:
| Product | wt. | Assay - percent or g/t | Distribution - percent | ||||||
| % | Cu | Zn | Cg* | S | Cu | Zn | Cg* | S | |
| Cg Conc | 5.7 | 1.16 | 1.75 | 12 | 5.72 | 8.8 | 3.9 | 96.4 | 6.7 |
| Cu 2nd Cl Conc | 2.2 | 25.5 | 5.08 | 0.32 | 34.3 | 75.6 | 4.5 | 1.0 | 15.6 |
| Zn 2nd Cl Conc | 2.6 | 0.45 | 56.1 | 0.06 | 32.9 | 1.5 | 57.2 | 0.2 | 17.4 |
| Zn Ro Tail | 79.5 | 0.04 | 0.06 | 0.01 | 1.47 | 4.6 | 1.9 | 1.6 | 23.9 |
| Feed (calc.) | 0.75 | 2.53 | 0.71 | 4.89 | |||||
*Cg =Carbon as Graphite
Testwork has demonstrated the ability to produce copper concentrates at or above 25% Cu with low Zn contamination and open circuit copper recoveries of just over 75%. Zinc demonstrated the ability to upgrade above 55% Zn with open circuit recoveries of 57% Zn. For both copper and zinc recoveries, locked cycle testing will be needed to validate improved recoveries contained within internally circulating middling streams.
Ore Sorting
Ore sorting amenability testing was undertaken to characterize material representing the Bur Deposit. Coarse crushed samples were selected by hand at Base Met Labs in Kamloops represent both waste/dilution and mineralized target areas and shipped for testing at the Steinert facility in Kentucky.
The material provided to Steinert was nominal 2.5 cm in size. The approach to sorting followed the same protocol applied to Rail and Tower properties; captured on the Company's May 1, 2020 News Release. Ore sorting demonstrated flexibility to preconcentrate feed material with varying mass rejection and recovered over 90% Cu and 97% Zn with just over 25% mass rejection. Complete sorting results are provided by Table 2.
Table 2: Ore Sorting Upgrade Results
| Products | wt. | Element (%) | Distribution | ||||||
| % | Cu | Zn | S | Cg* | Cu | Zn | S | Cg* | |
| Sorted Conc 1 | 40.7 | 1.90 | 4.85 | 10.3 | 0.32 | 77.2 | 93.9 | 73.0 | 15.4 |
| Sorted Conc 1-2 | 57.5 | 1.51 | 3.51 | 8.24 | 0.71 | 87.0 | 96.1 | 82.3 | 47.5 |
| Sorted Conc 1-3 | 74.0 | 1.23 | 2.76 | 6.89 | 0.79 | 91.1 | 97.1 | 88.4 | 67.7 |
| Feed | 1.00 | 2.10 | 5.76 | 0.86 | |||||
*Cg =Carbon as Graphite
QP
Mike Romaniuk P.Eng., VP Projects of Rockcliff, a Qualified Person in accordance with Canadian regulatory requirements as set out in NI 43-101, has read and approved the scientific and technical information that forms the basis for the disclosure contained in this press release.
About Rockcliff Metals Corporation
Rockcliff is a well-funded Canadian resource development and exploration company, with +1,000 tonne per day leased processing and tailings facility as well as several advanced-stage, high-grade copper and zinc dominant VMS deposits in the Snow Lake area of central Manitoba. The Company is a major landholder in the Flin Flon-Snow Lake Greenstone Belt ("Belt") which is home to the largest Paleoproterozoic VMS district in the world, hosting mines and deposits containing copper, zinc, gold and silver. The Company's extensive portfolio of properties totals approximately 4,500 square kilometres and includes eight of the highest-grade, undeveloped VMS deposits in the Belt.
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For further information, please contact:
Alistair Ross
President & CEO
Phone: (249) 805-9020
contact@rockcliffmetals.com
Cautionary Note Regarding Forward-Looking Statements: This news release includes forward-looking statements that are subject to risks and uncertainties. Forward-looking statements involve known and unknown risks, uncertainties, and other factors that could cause the actual results of the Company to be materially different from the historical results or from any future results expressed or implied by such forward-looking statements. All statements contained in this news release, other than statements of historical fact, are to be considered forward-looking. Although Rockcliff believes the expectations expressed in such forward-looking statements are based on reasonable assumptions, such statements are not a guarantee of future performance and actual results or developments may differ materially from those in the forward-looking statements.
The Canadian Securities Exchange does not accept responsibility for the adequacy or accuracy of this news release.