3 Nov 2016 09:00
Minco plc
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PROGRESS UPDATE ON RESEARCH PROGRAM INVESTIGATING CENTRAL MILLING FACILITY IN NEWFOUNDLAND
· Lundberg Cu-Pb-Zn-Ag-Au Deposit added to Central Milling Program
· Positive Metallurgical Results for all Five Deposits on Common Flotation Flowsheet
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TORONTO, 3 NOVEMBER 2016 - Minco Plc (AIM - "MIO") is pleased to provide an update on its ongoing research program to investigate the metallurgical and economic viability of utilizing a central milling facility to develop its volcanogenic massive sulphide ("VMS") Zn-Pb-Cu-Ag-Au base metal deposits located in central Newfoundland.
The preliminary test results confirm that selective zinc, lead and copper concentrates at marketable grades can be produced using a common flotation flowsheet. 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 metallurgical research program is being jointly undertaken with Canadian Zinc Corporation ("Canadian Zinc") and funded in part by the Research & Development Corporation of Newfoundland and Labrador ("RDC") through the GeoEXPLORE Industry-led program and is scheduled to be completed in December, 2016.
Since its inception in December 2015, the program has expanded its focus from four VMS deposits, two held by Minco (Bobbys Pond and Daniels Pond) and two held by Canadian Zinc (Lemarchant and Boomerang-Domino) to include Minco's Lundberg deposit, which because of its large size holds more contained zinc, copper and lead metal than the other four smaller deposits combined.
Minco's 100% owned Lundberg deposit is a large, near-surface open-pitable resource located on the north side of Red Indian Lake near the town of Buchans, NL. The deposit is comprised of base metal sulphide enriched stockwork mineralization located in the footwall to the previously mined, high-grade, Lucky Strike massive sulphide ore body, which was mined by ASARCO between 1926 and 1984. Since 2007, Minco has expanded the deposit to more than twice the size of original ASARCO estimate.
Table 1: Lundberg Deposit NI 43-101 Indicated & Inferred Resource Estimate (2013).
NSR ($US) Cut-off | Category | Rounded Tonnes | Zinc (Zn) % | Lead (Pb) % | Copper (Cu) % | Silver (Ag) g/t | Gold (Au) g/t |
15 | Indicated | 23,440,000 | 1.41 | 0.60 | 0.35 | 5.31 | 0.07 |
Inferred | 4,310,000 | 1.29 | 0.54 | 0.27 | 4.47 | 0.08 |
*Source: - Mineral Resource Estimate Technical Report on the Lundberg Deposit, Buchans Area, Newfoundland, Canada, April 26, 2013; filed on SEDAR
The key rational to include the Lundberg deposit was to fully assess all the known deposits in the district and to determine if Lundberg can enhance the economics of a central milling facility and the future development of this region's mineral resources. The potential benefits include:
· Increase Project Life - The additional tonnage contribution from the Lundberg deposit to a central milling facility could add considerably to the life of the project.
· Reliable Mill Feed - Open pit production from the Lundberg deposit could provide a very predictable and reliable source of mill feed that will limit potential issues related to maintaining underground mining rate from the other satellite deposits.
· Existing Infrastructure - the proximity of the Lundberg deposit to the town of Buchans provides for ready access to existing infrastructure as well as existing tailings facilities that could potentially be expanded (i.e. roads, electricity, labour).
Highlights of the DMS and Metallurgical Testing
The metallurgical test program completed by Thibault & Associates Inc. of Fredericton, New Brunswick was based on an assessment of pre-concentrating the ore prior to flotation using Dense Media Separation ("DMS") technology and the development of a process relative to the metallurgical characteristics of five deposits under development. The results of the bench scale test program have indicated an improved grade and recovery relationship for the production of Cu-Pb-Zn concentrates using a sequential flotation flowsheet.
Highlights of the testing program are provided below.
· Dense Media Separation - The bench scale DMS test program was completed to assess the amenability of mineralized samples from the deposits to physical upgrading (pre-concentration) at each site. Use of DMS processing technology would provide a potential means of reducing transportation costs from mine site to the milling facility and to maximize head grade and reduce downstream processing costs.
Results from pre-concentration of the samples by DMS (prior to flotation) was determined to be technically viable for semi-massive and stringer sulphide samples from the Lemarchant FW, Bobbys Pond and Lundberg deposits. Results from the testing are provided below. An economic assessment of processing ores with DMS technology is in progress to determine if there is a net benefit in reducing the mass of ore to process compared to the loss of payable metals to the floats (waste) product.
Sample | Overall Metal Recovery to Sinks + Fines at 70% Mass Recovery | |||||
Cu (%) | Pb (%) | Zn (%) | Au (%) | Ag (%) | ||
Lemarchant FW | 94.6 | 97.7 | 95.4 | 97.4 | 96.4 | |
Bobbys Pond SMS Comp | 98.3 | 98.6 | 99.1 | 95.6 | 95.6 | |
Lundberg Y1-3 | 98.3 | 96.6 | 96.5 | 89.6 | 95.3 | |
Lundberg Y4-8 | 94.7 | 94.2 | 93.9 | 84.8 | 90.1 | |
Sample | Overall Upgrade Ratio (Sinks + Fines Relative to Feed) | |||||
Cu | Pb | Zn | Au | Ag | ||
Lemarchant FW | 1.35 | 1.4 | 1.36 | 1.39 | 1.38 | |
Bobbys Pond SMS Comp | 1.40 | 1.41 | 1.42 | 1.37 | 1.37 | |
Lundberg Y1-3 | 1.40 | 1.38 | 1.38 | 1.28 | 1.36 | |
Lundberg Y4-8 | 1.35 | 1.35 | 1.34 | 1.21 | 1.29 | |
· Common Flotation Flowsheet - Initial bench scale flotation tests were designed to compare two flowsheet options: 1) a bulk Cu/Pb-Zn flotation flowsheet and 2) a sequential Cu-Pb-Zn flotation flowsheet using various reagent schemes and alternative grind specifications.
Results from the initial flotation testing indicate the sequential Cu-Pb-Zn flowsheet provided the best overall performance for the original four deposits tested. Subsequent testing of the Lundberg Deposit samples indicates it is also amenable to the sequential Cu-Pb-Zn flotation flowsheet with improved concentrate grade and metal recoveries over previous metallurgical testing completed for the 2011 Lundberg Preliminary Economic Assessment.
· Flotation Testing - the bench scale metallurgical test work was aimed at assessing the amenability of the mineralized samples from the five deposits to a common flotation flowsheet. The test work serves as a first stage evaluation of developing a process flowsheet and the ability to process various base metal deposits of central Newfoundland.
Preliminary results from the bench scale batch flotation tests confirmed the production of selective zinc, lead and copper concentrates at marketable grades relative to smelter schedules. Based on the bench scale batch flotation tests (as an open circuit without recycle) and process simulation of the sequential flowsheet mass balance relative to the test program, the grade and recovery of concentrates for each deposit have been defined by the following Table and are not representative of lock cycle or pilot testing of the proposed flowsheet.
Cu Concentrate | Pb Concentrate | Zn Concentrate | |
(Grade/Recovery) | (Grade /Recovery) | (Grade /Recovery) | |
Deposit | (wt %) | (wt %) | (wt %) |
Boomerang | 25.7% / 63.4% | 55.4% / 71.2% | 49.8% / 91.7% |
Lemarchant MS | 33.7% / 78.1% | 69.4% / 82.4% | 60.8% / 90.7% |
Lemarchant FW | 31.0% / 90.1% | No concentrate | 59.8% / 96.9% |
Bobbys Pond | 30.9% / 83.8% | 76.5% / 69.3% [1] | 64.8% / 93.1% |
Daniels Pond | 18.1% / 54.6% | 74.0% / 76.8% [1] | 61.0% / 90.1% |
Lundberg Y1-3 | 30.1% / 86.2% | 72.1% / 83.1% | 61.1% / 78.7% |
[NOTE 1] Lead grade defined by the test program with added cleaning of the lead concentrate to reduce zinc and iron.
Economic Assessment
The metallurgical test programs are being followed-up with a Process Simulation and Cost Assessment model (AACE Class V - order of magnitude / conceptual assessment) to evaluate and identify the key factors impacting the operating economics of a centralized processing concept for the production of the base metal concentrates. Results from the conceptual economic assessment will be used to help optimize future exploration and development plans, by focusing on key factors that are critical to assessing the economic potential and viability of developing the central Newfoundland deposits through a central milling facility.
ABOUT MINCO PLC
Minco Plc, incorporated in the Republic of Ireland and listed on the AIM Market of the London Stock Exchange ("MIO"), is an exploration and development company currently engaged in zinc-lead exploration in Canada, the United Kingdom and Ireland, and is also evaluating its Woodstock manganese project in New Brunswick, Canada.
Minco also holds an approximate 26% shareholding in Xtierra Inc, (TSXV- "XAG"), which holds mineral properties in Mexico, and a 2% NSR royalty on the Curraghinalt gold property in Northern Ireland, currently being explored by Dalradian Resources Inc. (TSX-"DNA").
For further information contact:
Warren MacLeod: Director, President Buchans Minerals +1 709 725 0555
John F. Kearney: Chairman +1 416 362 6686
Danesh Varma: CFO & Company Secretary +44 (0) 8452 606 034
Peter McParland: Director - Ireland +353 (0) 46 907 3709
John Frain: Davy (NOMAD) +353 (0)1 6796363
Saif Janjua: (Corporate Advisor) (Broker, Beaufort Securities) +44 (0) 20 7382 8415
Website: www.mincoplc.com
Qualified Person
J. Dean Thibault, P.Eng., Senior Process Chemical Engineer of Thibault & Associates Inc. is the qualified person for this release and has reviewed the contents for accuracy and approved this release. Thibault & Associates Inc. are process chemical engineering firm specializing in process flowsheet development, plant design and process intensification assessment.
Cautionary Statement - Forward-Looking Information
This news release contains certain forward-looking information, including, among other things, the expected exploration of mineral properties. This forward looking information includes, or may be based upon, estimates, forecasts, and statements as to management's expectations with respect to, among other things, the timing of exploration, development and mining activities, the size and quality of mineral resources, progress in development of mineral properties, demand and market outlook for metals, future metal prices and treatment and refining charges, future trends for the company, and the financial results of the company. Mineral exploration and development is a speculative business including, among other risks, the failure to discover mineral deposits but also from finding mineral deposits that, though present, are insufficient in quantity and quality to return a profit from development and production. There can be no assurances that such statements will prove to be accurate and actual results and future events could differ materially from those anticipated in such statements. Mineral resources that are not mineral reserves do not have demonstrated economic viability. Inferred mineral resources are considered too speculative geologically to have economic considerations applied to them that would enable them to be categorized as mineral reserves. There is no certainty that mineral resources will be converted into mineral reserves.