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Rockridge Announces Inaugural NI 43-101 Resource Estimate for the Knife Lake Project

August 14, 2019

Vancouver, BC – Rockridge Resources Ltd. (TSX-V: ROCK) (OTCQB: RRRLF) (Frankfurt: RR0) (“Rockridge” or the “Company”) is pleased to announce the first NI 43-101 resource estimate for its flagship Knife Lake Project located in Saskatchewan, Canada (the “Knife Lake Project” or “Property”). Rockridge entered into an Option Agreement with Eagle Plains Resources Ltd. to acquire a 100% interest in the Property that covers the majority of the Knife Lake Cu-Zn-Ag-Co VMS deposit. The contiguous claims total 85,196 hectares and are located approximately 50 km northwest of Sandy Bay, Saskatchewan. A 357kV powerline runs within 16 km of the Knife Lake Deposit area, greatly enhancing the project’s infrastructure. 

Knife Lake VMS Project Map:


  • Recently completed diamond drilling program plus historical drill core provided data for completion of the first NI 43-101 resource estimate for the Knife Lake deposit.
  • Knife Lake is a near surface VMS deposit starting a few metres below surface and the deposit remains open at depth and along strike for potential resource expansion.
  • Indicated resources of 3.8 million tonnes at 1.02% CuEq (0.4% CuEq cut-off)
    • Or 3.8 MT at 0.83% Cu, 3.7 gpt Ag, 0.097 gpt Au, 82 ppm Co, 1740.7 ppm Zn
  • Inferred resources of 7.9 million tonnes at 0.67% CuEq (0.4% CuEq cut-off)
    • Or 7.9 MT at 0.53% Cu, 2.4 gpt Ag, 0.084 gpt Au, 53.1 ppm Co, 1454.9 ppm Zn
  • The deposit is a remobilized portion of a presumably larger “primary” VMS deposit; most of the historical work has consisted of shallow drilling at the deposit area with little regional work carried out and limited deeper drilling below the deposit.
  • A summer field program is set to commence to refine and prioritize numerous regional exploration targets on the highly prospective and under-explored property; additional news is forthcoming.  

Rockridge’s CEO, Grant Ewing, commented: “This first NI 43-101 resource estimate for the Knife Lake deposit represents an important milestone for the Company. The near surface resource serves as a great foundation for the project. The Company will now focus on expanding the resource by drilling off extensions to the known deposit and exploring for additional deposits in the immediate vicinity on the extensive Knife Lake landholding. The geologic setting of the Knife Lake district is similar to the world-class Flin Flon metals belt to the south, where numerous economic mines have been developed, implying high mineral potential for the underexplored Knife Lake property.”

Rockridge’s President, Jordan Trimble, commented: “This initial NI 43-101 resource estimate is a significant milestone for the Company. With the shallow Knife Lake deposit as a remobilized portion of a presumably larger primary VMS deposit, we are excited to commence a regional summer field program to unlock further value at the project through additional discoveries. There have been several other notable developments in the region including an upcoming 100,000m drill program planned by Rockcliff Metals as well as Hudbay Mineral’s new discovery near the Lalor mine. With several mineral properties in our portfolio, we will continue to execute on our value creation strategy of going into overlooked but prospective projects in prolific mining jurisdictions and using modern exploration methodologies to test new ideas and make new discoveries.”

Knife Lake Deposit NI 43-101 Resource Estimate:

The tables below summarize the sensitivity of the Knife Lake mineral resource estimate to cutoff grade, with the base case cutoff of 0.40% copper equivalent (CuEq) highlighted. The base case CuEq cutoff is equal to an NSR cutoff of approximately CDN $30/tonne and is based on processing costs of comparable deposits.

There are no known current environmental, permitting, legal, title, taxation, socio-economic, marketing, or political factors that could materially affect the mineral resource estimate. Factors that may affect the estimate are typical of any deposit and include; metal price assumptions, changes in interpretations of mineralization, metallurgical recovery assumptions, delays or other issues in reaching agreements with local or regulatory authorities and stakeholders, and changes in land tenure requirements or in permitting requirements.


Indicated Resource (effective date of June 12, 2019):

Cutoff Tonnage Grades   Metal Content
CuEq (%) (ktonnes) CuEq (%) Cu (%) Ag (gpt) Au (gpt) Co (ppm) Zn (ppm) NSR ($CDN) CuEq Mlbs Cu - Mlbs Ag - kOz Au - Oz
0.2 4,205 0.96 0.78 3.5 0.091 78.5 1634.4 70.85 89 72 473 12,357
0.4 3,836 1.02 0.83 3.7 0.097 82.0 1740.7 75.36 86 70 456 11,951
0.6 3,136 1.14 0.93 4.1 0.104 88.3 1855.1 83.87 78 64 413 10,466

CuEq = CU% + ZN%*0.398 + CO%*5.901+AUGPT*0.553+AGGPT*0.005

Inferred Resource (effective date of June 12, 2019):

Cutoff Tonnage Grades   Metal Content 
CuEq (%) (ktonnes) CuEq (%) Cu (%) Ag (gpt) Au (gpt) Co (ppm) Zn (ppm) NSR ($CDN) CuEq Mlbs Cu - Mlbs Ag - kOz Au - Oz
0.2 11,106 0.58 0.45 2.1 0.069 50.0 1261.8 42.50 141 110 750 24,601
0.4 7,902 0.67 0.53 2.4 0.084 53.1 1454.9 49.74 117 92 610 21,340
0.6 3,626 0.88 0.70 3.0 0.111 60.7 1734.1 65.28 71 56 350 12,963

CuEq = CU% + ZN%*0.398 + CO%*5.901+AUGPT*0.553+AGGPT*0.005

The mineral resources have been estimated in conformity with generally accepted CIM “Estimation of Mineral Resource and Mineral Reserves Best Practices” guidelines (CIM, 2014) and are reported in accordance with the Canadian Securities Administrators’ National Instrument 43-101 (CSA, 2018). Mineral resources are not mineral reserves and do not have demonstrated economic viability. There is no certainty that all or any part of the mineral resource will be converted into mineral reserve. The NI 43-101 resource estimate has an effective date of June 12, 2019.

The resource for the Knife Lake deposit has been confined within an open pit shape to define “reasonable prospects of eventual economic extraction” using the following input parameters:

Metal Price USD $ Units Recovery (%) Payables (%)
Cu 2.80 /lb 95 99
Zn 1.20 /lb 90 97
Co 18.00 /lb 89 97
Au 1300 /oz 80 96
Ag 17.00 /oz 55 90

In addition, an exchange rate of $CDN:$US of 0.77 has been used with a mining cost of CDN $1.30/tonne and a royalty of 2% applied to the NSR values. 

Interpolation for all metals has been done using 4 passes with anisotropic distances based on variography for 5 domains that have been created based on the mineralization. Ordinary kriging (OK) has been used as the final grades for all metals except Au which has final grades based on inverse distance squared (ID2) for better validation of the model. Outlier restriction of high grades for each metal and domain have been applied where deemed necessary based on cumulative probability plots (CPP) and percent of metal removed.

Interpolation parameters are summarized in the table below:

Domain Pass Composites Restrictions Anisotropic Search Distances (m)
Minimum # Maximum # Maximum/DH Major Minor Vertical
1 - 4 1 5 8 2 50 25 10
2 5 8 2 100 50 20
3 5 6 2 150 75 30
4 1 6 2 300 150 60
5 1 5 8 2 50 40 10
2 5 8 2 100 80 20
3 5 6 2 150 120 30
4 1 6 2 300 240 60

Classification to Indicated is based on a continuous volume of modelled blocks in the central area of the deposit with the average distance to at least 2 drillholes of up to 35m. All other interpolated blocks are considered Inferred with distances to drillholes as summarized in the above table.

Below is a link to a three-dimensional view of the Knife Lake block model illustrating the copper equivalent grade for the entire length of the deposit within Rockridge’s claims. The view is looking northwest with a grid size of 200m x 200m to indicate the scale.

Knife Lake Deposit 3D View - Modelled Blocks showing CuEq Grade:http://www.rockridgeresourcesltd.com/_resources/maps/Knife_Lake_Deposit_3D_View.jpg

Summer Exploration Program:

A summer field exploration program is scheduled to commence shortly and will focus on evaluating existing, highly prospective targets within the large landholding, with targets in the immediate vicinity of the Knife Lake deposit being prioritized. A subsequent program of geophysics and drilling is planned to test the highest priority targets.

Knife Lake contains typical VMS mineralogy which has been significantly modified and partially remobilized during the emplacement of granitic rocks. Therefore, the known deposit may represent a remobilized portion of a presumably larger “primary” VMS deposit based on general observations about the mineralogy, mineral textures and metal ratios in the deposit. Most of the historical work has consisted of shallow drilling at the deposit area with little regional work carried out and limited deeper drilling below the deposit. As a result, there is strong discovery potential both at depth and regionally.

Knife Lake Geology and History: 

The Knife Lake Project is interpreted to be a remobilized VMS deposit. The stratabound mineralized zone is approximately 15m thick and contains copper, silver, zinc, gold and cobalt mineralization which dips 30° to 50° eastward over a known strike-length within Rockridge’s claim area of 3,700 metres, and a known average down-dip extension of approximately 300 metres.  

Within the resource estimate block model volume there are 332 drillholes with a total assayed length of 7,253 metres drilled since the 1990’s era drilling, which have been used for grade interpolation.  Historic 1970’s and earlier drilling have not been used because grades could not be verified.

Knife Lake Deposit Map:

The deposit is hosted by felsic to intermediate volcanic and volcaniclastic rocks which have been metamorphosed to upper amphibolite facies. The deposit contains VMS mineralogy which has been significantly modified and partially remobilized during the emplacement of granitic rocks. The mineralization straddles the boundary between two rock units and occurs on both limbs of an interpreted overturned fold.

The Company completed twelve holes consisting of 1,053 metres of diamond drilling in the 2019 winter drilling program. This represented the first drilling on the property since 2001 and had two primary objectives: confirm the tenor of mineralization reported by previous operators and expand known zones of mineralization. Highlights from the drill program included previously reported hole KF19003 which intersected net-textured to semi-massive sulphide mineralization from 11.2m to 48.8m downhole. This 37.6 metre interval returned 2.03% Cu, 0.19 g/t Au, 9.88 g/t Ag, 0.36% Zn, and 0.01% Co for an estimated 2.42% CuEq. Additionally, previously reported drill hole KF19001 intersected net-textured to fracture-controlled sulphide mineralization from 7.5 metres to 40.6 metres downhole. This 33.1 metre interval returned 1.28% Cu, 0.12 g/t Au, 4.80 g/t Ag, 0.13% Zn, and 0.01% Co for an estimated 1.49% CuEq.


Knife Lake Plan Map and Drill Collar Locations:

Compilation and initial modelling indicate potential for expansion of the deposit at depth. The recent drilling focused on resource upgrade as well as infill drilling between historical holes. The program gave the Company’s technical team valuable insights into the property geology, alteration, and mineralization that will be applied to future regional exploration on the highly prospective and underexplored land package.  

Qualified Assurance Program and Quality Control Measures (“QA/QC”)

Rockridge implemented QA/QC protocols including insertion of duplicate, blank, and standard samples in all 2019 drill holes.  Check samples of 25 selected intervals from Leader Mining drilling in the 1990s were sent to ALS in North Vancouver, BC, Canada, for analysis. The historic samples were not consistently assayed for cobalt, lead and zinc so those comparisons are limited. Check assays returned acceptable results for all samples except one.

All lab internal standards and duplicates were within acceptable values. Core from Rockridge’s 2019 diamond drilling program was logged and sampled on site by staff of Terralogic Exploration Inc.  Whole core was sawn in half and a total of 609 samples were sealed and shipped directly to ALS Environmental in Saskatoon for internal transportation to ALS Geochemistry in North Vancouver for analysis.

Analysis consisted of 48 element four acid ICP-MS (ME-MS61) and gold (Au) 30 g Fire Assay – AA finish (Au-AA23). Over limit analysis were completed using the following analyses: Ore Grade copper (Cu), nickel (Ni) and zinc (Zn) – four acid ICP-AES (ME-OG62). A total of 33 QAQC samples were inserted over 12 drill core sample shipments, including 18 standards and 15 blanks. Standards and blanks from 2019 returned acceptable values.

Qualified Persons:

Stephen Kenwood, P.Geo., an independent qualified person visited the Knife Lake Property on May 15, 2018 and March 22, 2019 and is responsible for the geology and QAQC.

Sue Bird, P.Eng., Principal of Moose Mountain Technical Services (MMTS) is the QP for the Resource estimate and has reviewed the QAQC for the deposit. Tracey Meintjes, P.Eng., Principal of MMTS is the QP for the metallurgy including the processing and recovery estimates.

Grant Ewing, P.Geo., a “qualified person” for the purposes of National Instrument 43-101 - Standards of Disclosure for Mineral Projects, and is the CEO of Rockridge Resources Ltd., has reviewed and approved the scientific and technical disclosure in this news release.

About Rockridge Resources Ltd.

Rockridge Resources is a new publicly traded mineral exploration company focused on the acquisition, exploration and development of mineral resource properties in Canada, specifically copper and base metal projects. The Company's flagship project is the Knife Lake Project located in Saskatchewan, which is ranked as the #3 mining jurisdiction in the world by the Fraser Institute. The project hosts the Knife Lake deposit, which is a VMS, near-surface copper-cobalt-gold-silver-zinc deposit open along strike and at depth. There is strong discovery potential in and around the deposit area as well as at regional targets on the 85,196-hectare property. Rockridge’s goal is to maximize shareholder value through new mineral discoveries, committed long-term partnerships, and the advancement of exploration projects in geopolitically favourable jurisdictions.

Rockridge Resources Ltd.

“Jordan Trimble”


Jordan Trimble
President and Director

For further information contact myself or:
Nick Coltura
Corporate Communications
Rockridge Resources Ltd.
Telephone: 604-687-3376
Toll Free: 800-567-8181
Facsimile: 604-687-3119
Email: info@rockridgeresourcesltd.com


Forward Looking Statements:

Statements included in this announcement, including statements concerning our plans, intentions and expectations, which are not historical in nature are intended to be, and are hereby identified as, “forward-looking statements”. Forward-looking statements may be identified by words including “anticipates”, “believes”, “intends”, “estimates”, “expects” and similar expressions. The Company cautions readers that forward-looking statements, including without limitation those relating to the Company’s future operations and business prospects, are subject to certain risks and uncertainties that could cause actual results to differ materially from those indicated in the forward-looking statements.