The Buchans Base Metal Project is located in central Newfoundland and covers the former producing Buchans Mine and includes the Company’s undeveloped Lundberg deposit.
In January 2021, Buchans entered into a Collaboration Agreement with Boliden Mineral AB under which Boliden will evaluate the Company’s Buchans VMS property in Newfoundland for possible future investment and participation.
Boliden will contribute $600,000 to Buchans towards the costs of maintaining the Property and approved ongoing exploration and evaluation programs to be undertaken by Buchans on the Property during the Exclusivity Period. Boliden intends to complete its evaluation of the project during an exclusivity period ending December 31, 2021 2021 and the companies will negotiate the Earn-in and Option Agreement and the JV Agreement
The combination of Buchans’ in-depth, hands-on, knowledge of the historic Buchans camp with Boliden’s experience and technological expertise in near-mine exploration for VMS base metal deposits could lead to future discoveries of new buried, high-grade, orebodies and a revitalization of this world-renowned historic VMS mining camp. Boliden has had success in its near mine exploration for VMS deposits at the Garpenberg mine in Sweden and at the Tara mine in Ireland.
The Lundberg copper-zinc-lead-silver-(gold-barite) deposit is at the core of Buchans base metal project in the Buchans camp.
Buchans is located approximately 530 km by highway west of the provincial capital city of St. John’s and is accessible via paved Route 370 from its junction with the Trans-Canada Highway at the town of Badger, approximately 70 km north of Buchans. The nearest major airports are Gander International Airport and Deer Lake Regional Airport, which are located 128 km east and 181 km west of the town of Badger, respectively.
Access to the Lundberg deposit area for exploration purposes is by a network of paved and gravel roads extending from the community of Buchans in central Newfoundland, providing year-round access to the property. The Lundberg Deposit is situated at the southwest periphery of the community of Buchans.
On March 1, 2019 Buchans announced a new updated pit-constrained Mineral Resource Estimate for the Lundberg base metal deposit, located at the former Lucky Strike mine site, and a NI 43-101 Technical Report was filed on April 15, 2019. The new 2019 Mineral Resource Estimate, containing more than 1.25 billion pounds Zinc Equivalent, with 98.7% of the Mineral Resources in the Indicated category, demonstrates a significantly more robust project which provides compelling rationale to undertake a new updated Preliminary Economic Assessment, or a Preliminary Feasibility Study, to assess Lundberg as a stand-alone open-pit mineral resource development with a low strip ratio, optimally situated on a brownfields site with excellent infrastructure.
Lundberg Deposit In-Pit Mineral Resource Estimate – Effective February 28, 2019
|NSR Cut-off (USD/t)||Category||Tonnes||Zn %||Pb %||Cu %||Ag g/t||Au g/t||Zn Eq. %||NSR (USD/t)||Strip Ratio|
- Mineral Resource tonnages have been rounded to the nearest 10,000. Totals may vary due to rounding.
- Price assumptions used were US $1.20/lb Zn, $1.00/lb Pb, $3.00/lb Cu, $1,250/oz Au, and $17/oz Ag.
- Metallurgical recoveries to concentrates are based on the Central Milling Facility Assessment (Thibault & Associates Ltd., 2017). Metal recoveries are 83.0% Cu, 13.3% Au, and 7.84% Ag in the copper concentrate, 84.3% Pb, 10.5% Au, and 50.3% Ag in the lead concentrate, and 87.2% Zn, 8.28% Au, and 14.8% Ag in the zinc concentrate.
- Net Smelter Return (NSR) USD/t values were determined by calculating the value of each Mineral Resource model block using an NSR calculator prepared by Stantec Consulting. The NSR calculator uses the stated metal pricing, metallurgical recoveries to concentrates, concentrate payable factors and current shipping and smelting terms for similar concentrates.
- Zinc Equivalent metal grade (Zn Eq. %) was calculated as follows using metal pricing, metallurgical recoveries to concentrates, and concentrate payable factors as applied in the NSR calculator: Zn Eq % = Zn % + ((Cu % x 22.046 x 0.8020 x 3) + (Pb % x 22.046 x 0.8010 x 1) + (Au g/t / 31.10348 x 0.2198 x 1250) + (Ag g/t / 31.10348 x 0.6514 x 17))/(1.20 x 22.046 x 0.7412).
- The Mineral Resource pit shell was developed and optimized by MineTech International Limited. Optimization parameters include: mining at US $3 per tonne, processing at US $15 per tonne, and G&A at US $2 per tonne (total US $20).
- A cut-off value of $20 USD/t NSR within the optimized pit shell was used to estimate Mineral Resources.
- Mineral Resources were interpolated using Inverse Distance Squared methods applied to 1.5 metre downhole assay composites.
- Results of an interpolated Inverse Distance Squared bulk density model (g/cm3) were applied.
- Mineral Resources are considered to reflect reasonable prospects for economic extraction in the foreseeable future using conventional open pit mining methods.
- Mineral Resources do not have demonstrated economic viability.
- This estimate of Mineral Resources may be materially affected by environmental, permitting, legal title, taxation, socio-political, marketing, or other relevant issues.
The 2019 Mineral Resource Estimate was prepared by Mercator Geological Services Limited. The pit shell was developed and optimized by MineTech International Limited. Projected metal recoveries are based on the previous Central Milling Facility Assessment by Thibault & Associates Ltd and the net smelter return (“NSR”) calculator as prepared by Stantec Consulting Ltd.
In summary, the Lundberg deposit is now estimated to host In-pit Indicated Mineral Resources containing 1.25 billion pounds Zinc Equivalent as well as In-pit Inferred Mineral Resources containing 0.037 billion pounds Zinc Equivalent using an NSR cut-off at US$20 per tonne. These resources are contained within an optimized model pit shell measuring 860 metres by 650 metres and extends to a maximum depth of 240 metres. The In-Pit constrained resource has a strip ratio of 2.9 of which approximately 98.7% of the resources are assigned to the Indicated category resources.
While the 2019 Mineral Resource Estimate excludes significant volumes of mineralization within the Lundberg deposit from classification as Mineral Resources, it should be noted that much of the excluded volume lies beneath the bottom of the current pit shell and has potential to be included in future optimized pit shells subject to changes in metal prices or other parameters defined for future optimization and mineral resource estimation.
The new 2019 Mineral Resource Estimate updated the Lundberg deposit to a more robust, pit-constrained resource,that is exemplified by its large inventory of Indicated category resources and represents a significant improvement over previous resource estimates. Through completion of a large amount of additional infill core drilling, extensive relogging of archived drill core, database upgrading and detailed deposit model studies in the intervening years, the 2019 Mineral Resource Estimate reflects a 97.8% conversion of 2011 PEA Ultimate Pit Design Inferred Mineral Resources to Indicated Mineral Resources at comparable grades and a slightly lower strip ratio.
The information relating to the Lundberg deposit has been largely extracted from the report entitled, “NI 43‐101 Technical Report and Mineral Resource Estimate On The Lundberg Deposit, Buchans Area, Newfoundland And Labrador, Canada” dated February 28th, 2019 prepared by Matthew Harrington, P. Geo., Michael Cullen, P.Geo., Shaun O’Connor, P. Geo., Timothy McKeen, P. Eng., and Douglas Roy, P. Eng. as Independent Qualified Persons as well as Paul Moore, P. Geo., and David Butler, P. Geo. as Qualified Persons, as defined by NI 43-101, as filed on SEDAR on April 15, 2019.
The Lundberg Report is intended to be read as a whole document, and sections should not be read or relied upon out of context. The technical information in the Lundberg Report is subject to the assumptions and qualifications contained in the Lundberg Report. For readers to understand the technical information on Lundberg in this document, they should read the Lundberg Report (2019) filed under the Company’s profile on www.sedar.com in its entirety.
Based on work carried out for the 2019 Mineral Resource estimation, Mercator is of the opinion that the Lundberg deposit has been sufficiently delineated by drilling to support Pre-feasibility (PFS) or Feasibility level studies, and that additional infill resource delineation drilling is not required for this purpose.
Mercator’s primary recommendation arising from the current Mineral Resource Estimate program is that an updated assessment of the Lundberg deposit’s economic potential be completed as the next phase of project evaluation. This could take the form of a new Preliminary Economic Assessment or an internal economic study leading to a decision to proceed directly to a PFS assessment of Lundberg Deposit economics.
Additional metallurgical testing would be required to support a future Preliminary Economic Assessment or Pre-Feasibility Study Assessment. Pre-concentration using dense media separation or ore sorting will improve mill feed grades, reduce the size of the milling facility or reduce mill feed transportation requirements should an offsite milling facility be considered. Future economic studies are therefore recommended to determine any potential savings with pre-concentration versus metal loss from the upgrading process.
2019 Deposit Optimization Study
Based on recommendations of the 2019 Mineral Resource Estimate, the Company engaged Stantec Consulting Limited of Fredericton, New Brunswick to undertake a deposit optimization study of the Lundberg deposit evaluating potential options for Lundberg’s development as a stand-alone open-pit resource. The study incorporated updated parameters determined by the Company’s continued technical assessments of the deposit since completion of a Preliminary Economic Assessment of the project in August of 2011. These parameters include revised metallurgical assumptions including assumptions determined by bench-scale metallurgical test work completed in 2017. In addition, Stantec also evaluated various development, mining and processing options
and scenarios, as well as reviewed tailings disposal options and shipping port alternatives.
The purpose of the Stantec study was to prepare a high-level options assessment for use internally by Buchans to assist with planning for future work on the Lundberg project.
The Stantec study evaluated several variables, including:
- Potential pit shell sizes and production rates.
- Potential to stockpile low-grade material.
- Option to develop a new concentrator at the Lundberg site versus re-use of an existing third-party mill located in the central Newfoundland area.
- The optional use of dense media separation (DMS) technology to pre-concentrate the resource material ahead of milling.
- Tailings disposal options based on expansion of the existing tailings infrastructure at site.
- Concentrate transport and port shipping alternatives.
- Among the recommendations of the study are that additional metallurgical testing is recommended to support a Preliminary Economic Assessment; that further work be undertaken to further assess potential application of a stockpiling strategy; and that tailings management options be further evaluated.
The results and conclusions of the Stantec study will now be utilised to focus the Company’s approach towards completion of an updated assessment of the Lundberg deposit’s economic potential in the form of a new Preliminary Economic Assessment as the next phase of the project evaluation.
The Lundberg deposit is favourably situated on a brownfields site with excellent infrastructure, including access by provincially maintained paved roads, power, water and other infrastructure. The Lundberg project is located in the Province of Newfoundland and Labrador, one of the top mining jurisdictions in Canada, and the Company has established a positive and cooperative relationship with the immediately adjacent, former mining town of Buchans.
2016 Testwork and Metallurgical Studies
During 2016, Buchans, in a collaboration agreement with Canadian Zinc Corporation ( now NorZinc Ltd. (TSX:NZC)) successfully completed a research programme to evaluate the metallurgical characteristics of their respective volcanogenic massive sulphide (“VMS”) Zn-Pb-Cu-Ag-Au base metal deposits in central Newfoundland.
The metallurgical research study demonstrated that the ore from Buchans Lundberg, Daniels Pond and Bobbys Pond deposits can be successfully processed in a central mill using a sequential flotation flowsheet, and that selective zinc, lead and copper concentrates at marketable grades can be produced from these deposits.
The programme focused its evaluation on five VMS deposits, three held by Buchans (Lundberg, Bobbys Pond and Daniels Pond) and two held by Canadian Zinc (Lemarchant and Boomerang-Domino). The Lundberg deposit is the largest, most advanced property in terms of resource definition, mine planning (with the potential to have an open pit mine), metallurgical testing and economic studies completed to date. All the other mineral deposits (Bobbys Pond, Daniels Pond, Lemarchant and Boomerang-Domino) are smaller, higher grade deposits, amenable to underground mining, that may not individually support a mine and processing operation. The principal goal of the research program was to assess the technical and economic viability of developing a number of these mineral deposits utilizing a common central processing facility.
The metallurgical portion of the program was successful in confirming that selective zinc, lead and copper concentrates at marketable grades can be produced using a common flotation flowsheet for all five deposits. The positive results from the metallurgical test program strongly support the development of the sequential flotation technology for processing of the central Newfoundland deposits using a centralized processing facility.
The positive results of the research project provide valuable direction to guide future exploration on Buchans central Newfoundland volcanogenic massive sulphide (“VMS”) Zn-Pb-Cu-Ag-Au base metal deposits and the conceptual economic modelling provided key information on which to focus future economic studies and development plans for advancing the development of the Lundberg and satellite deposits using a central milling facility.
Buchans Resources completed this positive PEA on an earlier resource estimate and therefore the 2011 PEA is now considered an historic and should not be relied upon.
Earlier Mineral Processing and Metallurgical Testing
In 2010, BMC retained SGS Lakefield Research Limited (“SGS”) of Lakefield, ON to carry out mineral processing and metallurgical testing on three representative samples of mineralized material from the Lundberg and Engine House zones. Results of this work were used by Coley at al. (2011) in the PEA prepared by Wardrop.
The mineralization tested by SGS consisted of stockwork style Cu, Pb and Zn sulphides in association with non-sulphide phases such as quartz, chlorite and lesser amounts of barite. The only copper bearing sulphide mineral identified was chalcopyrite, the only lead mineral present was galena, and the zinc mineralization occurred exclusively as sphalerite. Iron was distributed in primary sulphides including chalcopyrite, sphalerite, galena and pyrite. There was no arsenopyrite present as quantified by the associated study of mineralogy.
Metallurgical process development studies focused on flotation recovery of copper and lead followed by zinc. After completion of testing, the most appropriate flow sheet for processing of future mineralization, typified by the sample material, was assembled. Initial grinding of mill feed to 80% passing 52 μm was established for flotation circuit feed materials.