Rockcliff Files Updated Rail Deposit Mineral Resource Estimate 1.17M Indicated Tonnes at 3.52% Copper Equivalent and 0.73M Inferred Tonnes at 4.09% Copper Equivalent
Sudbury, May 15, 2020 - Rockcliff Metals Corp. (CSE: RCLF) (FSE: RO0) (WKN: A2H60G) ("Rockcliff" or the "Company") is pleased to announce the filing of a National Instrument 43-101-Standards of Disclosure for Mineral Projects ("NI 43-101") technical report titled "Technical Report and Updated Mineral Resource Estimate of the Rail Project, Manitoba, Canada" (the "Technical Report") prepared by P&E Mining Consultants Inc. ("P&E"). The Rail Property is part of the Company's Manitoba property portfolio and is located within the prolific Flin Flon-Snow Lake Greenstone Belt. The Technical Report is available for download on the Company's SEDAR issuer profile at www.SEDAR.com and the Company's website at http://rockcliffmetals.com. Highlights of the Differences in the Technical Report Compared to the Previous Mineral Resource Estimate Include:
- Indicated Mineral Resource tonnes increased by 42% (1.17Mt vs. 0.82Mt);
- Indicated contained copper increased by 27% (70.2M lbs vs. 55.1M lbs);
- Inferred Mineral Resource tonnes of 0.73Mt @ 4.09% CuEq containing 50.0M lbs of copper;
- Indicated contained gold increased by 72% (30.0k oz vs. 17.4k oz);
- Indicated contained zinc increased by 34% (22.0M lbs vs. 16.3M lbs); and
Indicated contained silver increased by 37% (334.3k oz vs. 243.3k oz.
Alistair Ross, President and CEO commented, "The reason for targeting the Rail deposit in our overall drill strategy was to identify a third possible mine alternative in addition to the Tower and Talbot deposits. Our drilling increased the indicated tonnes by nearly 40% and added 70Mlbs of copper. Additionally, we added in the inferred category 730kt and 50M pounds of copper. This increase in tonnage, pounds of copper and resource confidence on the Rail Deposit is a truly exciting result and will be an important part of our Preliminary Economic Assessment that is currently underway. With the deposit still open along strike to the south and at depth we look forward to exploring the potential for further growth of the existing Rail deposit in 2020."
The Technical Report prepared by P&E with an effective date of March 31, 2020 is summarized below.
Rail Deposit Updated Mineral Resource Estimate at 1.5% CuEq cut-off March 27, 2020(1-10)
| Classification | Tonnes (k) | Cu (%) | Zn (%) | Au (g/t) | Ag (g/t) | CuEq (%) | Cu (Mlbs) | Zn (Mlbs) | Au (koz) | Ag (koz) | CuEq (Mlbs) |
| Indicated | 1,168 | 2.73 | 0.86 | 0.80 | 8.90 | 3.52 | 70.2 | 22.0 | 30.0 | 334.3 | 90.7 |
| Inferred | 728 | 3.11 | 0.72 | 1.11 | 8.54 | 4.09 | 50.0 | 11.6 | 25.9 | 199.7 | 65.6 |
1) Mineral Resources which are not Mineral Reserves do not have demonstrated economic viability. The estimate of Mineral Resources may be materially affected by environmental, permitting, legal, marketing, or other relevant issues.
2) Mineral Resources were estimated using the Canadian Institute of Mining, Metallurgy and Petroleum ("CIM"), CIM Standards on Mineral Resources and Reserves, Definitions and Guidelines prepared by the CIM Standing Committee on Reserve Definitions and adopted by CIM Council.
(3) The Inferred Mineral Resource in this estimate has a lower level of confidence that that applied to an Indicated Mineral Resource and must not be converted to a Mineral Reserve. It is reasonably expected that the majority of the Inferred Mineral Resource could be upgraded to an Indicated Mineral Resource with continued exploration.
(4) Approximate Jan 31/20 two year trailing average US$ metal prices used were $3/lb Cu, $1.10/lb Zn, $1,350/oz Au and $16.50/oz Ag. The US$: CDN$ exchange rate used was 0.77.
(5) Respective process recoveries for Cu, Zn, Au, Ag were 95%, 80%, 80%, 80%.
(6) Respective smelter payables for Cu, Zn, Au, Ag were 96.5%, 85%, 90%, 90%.
(7)Respective USD Cu and Zn smelter treatment charges used were $80/tonne and $250/tonne with concentrate freight of CDN$65/tonne.
(8) CuEq% was calculated as follows: Cu% + (Zn % x 0.220) + (Au g/t x 0.673) + (Ag g/t x 0.008).
(9) The 1.5% CuEq cut-off is approximately equivalent to CDN$100/tonne project operating costs.
(10) Contained metal totals may differ due to rounding.
Figure 1: Rail Indicated and Inferred Resource, looking west.
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Resource Estimate Methodology
The Mineral Resource Estimate reported herein, considered drilling information available up to February 10, 2020 and was evaluated using a geostatistical block modeling approach constrained by polymetallic mineralization wireframes utilizing Geovia GEMSTM modelling software. The evaluation of the Mineral Resource Estimate involved CuEq cut-off value determination, cross-sectional polyline interpretation, constraining wireframe creation, compositing, grade capping, variography, grade Interpolation and Mineral Resource Estimate quantification.
A total of 97 drill holes (totalling 32,767 metres) from the entire database were reviewed and 74 of those drill holes (totalling 23,505 metres) were utilized to create the constraining wireframes which have an overall strike length of 960 metres, down dip projection of 515 metres and average true width of 1.6 metres. There were 316 assays captured by the constraining wireframes that were combined into 206 composites with an average core length of 1 metre. A grade capping evaluation was performed on the composites and Cu, Au and Zn were capped at 11%, 7g/t and 5%, respectively, while no capping was required for Ag. The capped composites were evaluated with variography to determine the grade interpolation search ellipsoid ranges for grade interpolation and classification. The Indicated Mineral Resource classification search ranges were 65 metres along strike, 65 metres down dip and 15 metres across dip. In order for a model block to be coded with an Indicated classification, its centroid must be able to see a minimum of 4 composites from at least 2 drill holes. Grade interpolation was undertaken with the ID2 method for Cu and Zn and ID3 for Au and Ag. The bulk density model was interpreted with ID2 from 37 bulk density composites with a single search ellipse pass. The resulting block model utilized blocks that were 2 metres in the X direction, 5 metres in the Y direction and 5 metres in the Z direction. The subsequent block model grades and tonnages were quantified for the Mineral Resource Estimate at a 1.5% CuEq cut-off value.
Neither Rockcliff's Qualified Person, Ken Lapierre, P.Geo., nor P&E's Qualified Person, Eugene Puritch, P.Eng., nor management of Rockcliff are aware of any known environmental, permitting, legal, title, taxation, socio-political, marketing or other relevant issues that may materially affect the estimate of the Mineral Resource.
Quality Control and Quality Assurance
Samples of half core were packaged and shipped directly from Rockcliff's core facility in Snow Lake to TSL Laboratories (TSL), in Saskatoon, Saskatchewan. TSL is a Canadian assay laboratory and is accredited under ISO/IEC 17025. Each bagged core sample was dried, crushed to 70% passing 10 mesh and a 250g pulp is pulverized to 95% passing 150 mesh for assaying. A 0.5g cut is taken from each pulp for base metal analyses and leached in a multi acid (total) digestion and then analyzed for copper, lead, zinc and silver by atomic absorption. Gold concentrations are determined by fire assay using a 30g charge followed by an atomic absorption finish. Samples greater than the upper detection limit (3000 ppb) are reanalyzed using fire assay gravimetric using a 1 assay ton charge. Rockcliff inserted certified blanks and standards in the sample stream to ensure lab integrity. Rockcliff has no relationship with TSL other than TSL being a service provider to the Company.
The Mineral Resource Estimate for the Rail Deposit disclosed in this press release has been estimated by Mr. Yungang Wu, P.Geo. an associate geologist of P&E and Eugene Puritch, P.Eng., President of P&E, both independent of Rockcliff. By virtue of their education and relevant experience Messrs. Wu and Puritch are "Qualified Persons" for the purpose of National Instrument 43-101. Mr. Puritch has read and approved the technical contents of this press release as it pertains to the disclosed Mineral Resource Estimate.
Ken Lapierre P.Geo., VP Exploration 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 a fully functional +1,000 tpd leased processing and tailings facility as well as several advance-staged, 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 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 over 4,500 square kilometres and includes eight of the highest-grade, undeveloped VMS deposits in the Belt.
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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.
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