(PLYMOUTH MANGANESE-IRON DEPOSIT)
NEW BRUNSWICK, CANADA
The Woodstock Project is located in western New Brunswick, Canada, approximately 5 km west of the town of Woodstock and 15 km east of the town of Houlton, Maine, USA. Comprised of Mineral Claim Number 5472, that contains 232 mineral claim units (5,875 ha), it includes the Plymouth Deposit and is 100% owned by CDMN. CDMN is also the owner of surface rights covering an area of 53 ha within Mineral Claim 5472 that cover a portion of the Plymouth Deposit.
The Woodstock Project is well positioned with respect to infrastructure. In addition to proximity to several towns and the provincial capital, a railway line is accessible in nearby Houlton, Maine and grid electrical power is readily accessible. The extensive surface drainage systems present in the Saint John River watershed provide readily accessible potential water sources for incidental exploration use such as diamond drilling. They also provide good potential as higher volume sources of water such as those potentially required for future mining and milling operations.
Previous Work Programs
In 2010, Tetra Tech (formerly Wardrop Engineering Inc.) was engaged to review and update the two processes that had generated positive operating margins in the earlier work carried out by Witteck. Results of the Tetra Tech study were for internal working purposes only but were succeeded by more comprehensive economic and hydrometallurgical reviews undertaken by Thibault and Associates Ltd. (Thibault).
In 2011, a five-hole (1,040 m) core drilling program was completed and further work by Thibault was focused on bench scale hydrometallurgical testing to confirm and optimize the process for leaching manganese from typical mineralization.
In 2013, 15 additional diamond drill holes were completed (4,082 m) along 7 section lines separated by intervals of approximately 100 m along the length of the deposit. The drilling programs account for the majority of drill hole and analytical data used in the current mineral resource estimate. However, Mercator also included validated results for 6 surface historical diamond drill holes completed in 1985 and 1987 (1,040 m) and two trenches competed in 1987 by a previous operator that were incorporated as horizontal drill holes.
Results of the 2011 and 2013 drilling programs demonstrate continuity of deposit extent and grade consistency across significant mineralized widths. Examples of representative intercepts from different deposit areas include:
- 11.41% Mn over 45.0 m in hole PL-11-006;
- 11.43% Mn over 89.0 m in hole PL-11-007;
- 11.28% Mn 217.4 m in hole PL-13-022A; and
- 9.32% over 202.0 m in PL-13-020.
Mercator prepared a mineral resource estimate based on the validated drilling and trenching results in 2013 and subsequently updated this estimate in 2014 to support a Preliminary Economic Assessment (PEA) of the Plymouth Deposit that was prepared by Terta Tech. Tetra Tech, Thibault and Associates Inc. (Thibault) and Mercator contributed to this assessment and the associated NI 43-101 Technical Report.
2021 Mineral Resource Estimate
The mineral resource estimate, outlined in the 2021 NI 43-101 Technical Report, is based on validated results of the 2011 and 2013 drilling programs, plus validated results of five drillholes and two trenches completed in 1987. The mineralized zone was modeled as a folded, stratiform manganese-iron deposit occurring within a northeast striking, steeply dipping host sequence of red and grey siliciclastic sedimentary rocks using GEOVIA (formerly Gemcom) Surpac™ (Surpac™) version 6.4.1 deposit modeling software.
Drilling-defined mineralization within the resource estimate block model occurs along a 700 m strike length and reaches a maximum width of approximately 200 m in the central deposit area. Inverse Distance Squared (ID2) interpolation methods and 3 m downhole assay composites were used to assign manganese, iron, and specific gravity values within the block model, with block dimensions of 10 m (x) by 10 m (y) by 10 m (z). Capping of metal grades was not deemed necessary. Metal grade assignment was peripherally constrained by two separate wire-framed solid models based on sectional geological interpretations for the deposit and a minimum included grade of 5% manganese over 12 m in the respective downhole direction of each drillhole. The predominant manganese mineral in the deposit is manganese carbonate (MnCO3). AGP Mining Consultants Inc. (“AGP”) provided pit optimization services that defined a cut-off value of 5% manganese for definition of mineral resources within the pit shell. This reflects conceptual production of 50% MSM and 50% HPMSM at a manganese total recovery factor of 85% and long-term prices of $1500/tonne and $935/tonne for HPMSM and MSM, respectively.
Table 1.1: Plymouth Manganese-Iron Deposit Mineral Resource Estimate – Effective November 10, 2021
|Type||Mn % Cut-off||Category||Rounded Tonnes||Mn %||Fe %|
1) Mineral resources were prepared in accordance with the CIM Standards (2014) and CIM MRMR Best Practice Guidelines (2019).
2) Mineral resources are defined within an optimized conceptual pit shell with average pit slope angles of 45⁰ in bedrock and 20⁰ in overburden
3) Pit optimization parameters include: pricing of US$1500 /tonne for High Purity Manganese Sulphate Monohydrate – 32% Mn (HPMSM – 32 % Mn), US$ 935/tonne for Manganese Sulphate Monohydrate – 32% Mn (MSM – 32%Mn), exchange rate of CDN$1.30 to US$ 1.00, mining at CDN $6.50/t, combined processing and G&A (1000 tpd) at CDN $193.22/t processed and a process recovery of manganese to MSM and HPMSM of 85%. Iron was not considered in the pit optimization but has potential for future commercial value.
4) Mineral resources are reported at a cut-off grade of 5 % manganese within the optimized conceptual pit shell. This cut-off grade reflects total operating costs used in pit optimization and is used to define “reasonable prospects for eventual economic extraction” by open pit mining methods.
5) Mineral resources were estimated using Inverse Distance Squared methods applied to 3 m downhole assay composites. No grade capping was applied. Model block size is 10 m (x) by 10 m (y) by 10 m (z).
6) Bulk density was estimated using Inverse Distance Squared methods applied to drill core sample data; it is assumed that specific gravity approximates bulk density for the materials modelled.
7) Mineral resources may be materially affected by environmental, permitting, legal, title, taxation, sociopolitical, marketing, or other relevant issues
8) Mineral resources are not mineral reserves and do not have demonstrated economic viability.
9) Mineral resource tonnages are rounded to the nearest 10,000.
Table 1.2: Plymouth Manganese-Iron Deposit Cut-off Grade Sensitivity Analysis Within Resources
|Type||Mn % Cut-off||Category||Rounded Tonnes||Mn %||Fe %|
This table shows sensitivity of the November 10, 2021, mineral resource estimate to cut-off grade. The base case at a cut-off value of 5.00% manganese is bolded for reference.
Well defined opportunities to expand current mineral resources exist in the immediate strike and dip extension areas of the mineralized zones that comprise the currently defined deposit. These are highest in resource expansion priority. The historically explored Hartford manganese-iron deposit that is held by CMC and is a short distance from the Plymouth deposit has not been drilled by CMC to date but has good potential for definition of new mineral resources.