The Redmoor Project is located between the village of Kelly Bray and the small town of Callington in southeast Cornwall, United Kingdom, approximately 25 km by road from the city and port of Plymouth, and 40 km from the recently commissioned Drakelands (Hemerdon) tungsten mine and processing plant. The area has well-established infrastructure and is located in the historically significant Cornish tin – tungsten – copper mining district.
Redmoor Project Location Map
The original Redmoor Mine is one of a group of mines (Redmoor, Holmbush and Kelly Bray) that were opened in the 18th century and continued operating until 1892 when they were forced to close due to low tin prices. Sections of the Redmoor Mine were re-opened between 1907 and 1914 and again in 1934. Historical records show operations at the Redmoor Mine, Kelly Bray Mine, and Wheal Florence Mine. The license area has records of the production of 574 tonnes of tin, 268 tonnes of WO3, 852 tonnes of copper, 153 tonnes of lead and 9,179 ounces of silver.
In October 2012, NAE acquired a 100% interest in the Redmoor Tungsten-Tin-Copper project through an exploration license and option agreement with the owner of the mineral rights. These rights cover an area of approximately 23 km2, including the Redmoor Project. The exploration license was granted for an initial period of 15 years with modest annual payments. The license is now held by subsidiary Cornwall Resources Limited (CRL).
CRL has the right to a 25 year mining lease, extendable by a further 25 years, which can be exercised at any time during the term of the exploration license. The mining lease permits commercial extraction of the minerals, subject to obtaining planning and other approvals, and is subject to a 3% net smelter return royalty payable to the mineral right owner once commercial production has commenced. Surface land access for exploration drilling and mining over part of the Redmoor deposit is also included in these agreements.
In 2016, Strategic Minerals plc (SML), an AIM listed company, entered a Joint Venture with NAE. Following investment by SML, which largely funded the 2017 drill program NAE and SML are now equal 50% shareholders of CRL.
The geology of the Redmoor Project is typical of other established mining areas of Cornwall. Tin, tungsten and sulphide mineralisation is spatially related to granite intrusions, which caused mineralising fluids to be mobilised along fractures and faults in host rocks. Redmoor is located adjacent to the Kit Hill granite intrusion, which is the focus of a number of historic mines, both within and contiguous to the east of the CRL mineral rights.
At Redmoor, tungsten and tin-oxide, and other base metal sulphide mineralisation occurs both in discrete veins or lodes (e.g. Johnson’s Lode, Kelly Bray Lode) and within a zone of numerous closely-spaced sub-parallel narrow mineralised quartz-veins known as the Sheeted Vein System (SVS). The SVS contains High Grade Zones where there is a higher density of mineralised quartz veins. These High Grade Zones within the SVS form the basis of the current, 2018 Redmoor High Grade Inferred Resource.
3D View of the Redmoor Deposit Looking South East
South West Minerals Limited (SWM) completed a drilling program at Redmoor between 1980 and 1983 comprising 35 diamond drillholes (totalling 12,146 m) to a maximum depth of 600 m.
The majority of the SWM drillholes were angled holes designed to intersect true thickness of the target lodes. All holes were downhole surveyed. Core was split and assayed for metals including tin, tungsten and copper in mineralised zones.
Two metallurgical testwork programmes were undertaken on composited samples of crushed diamond drill core. The results of this testwork was used by SWM for flowsheet and engineering design of the processing plant. SWM also undertook mine design and feasibility studies aimed at constructing a mine and processing plant at Redmoor.
The work of SWM came to an end in the mid-1980s as a result of the tin price crash resulting from the collapse of the International Tin Council. The resource potential outlined by SWM was left in the ground, offering an opportunity when metal prices recovered.
In 2015 NAE completed a detailed review of SWM’s metallurgical testwork and, through its consultant, Devlure, concluded that the Redmoor ore is coarse grained, is a simple, low-cost ore to process and that overall process recoveries of 68% tin, 72% tungsten, and 35% – 85% copper (depending on flowsheet design) are expected.
In 2017 Cornwall Resources Limited (“CRL”) drilled 20 diamond holes for 7,046 m in total. This program was successful in identifying high-grade zones within the SVS which form the basis of the 2018 High Grade Inferred Resource.
CRL 2017 Boreholes, Historic Boreholes and Surface Geology
Minimising community and environmental impacts is CRL’s first priority in all exploration activities it undertakes on site. There has been positive community engagement throughout the 2017 drilling program with 14 community meetings held to date. No complaints have been received from the local community despite drilling operations being in relatively close proximity to residential and rural properties. CRL has also aimed to maximise local employment and collaboration with local universities.
2018 High Grade Inferred Mineral Resource
Redmoor 2018 Inferred Mineral Resource Estimate
|High-Grade Zones in Sheeted Vein System||4.5||0.37||0.25||0.57||1.00|
 Equivalent metal calculation notes; Sn(Eq)% = Sn%*1 + WO3%*1.43 + Cu%*0.40. Commodity price assumptions: WO3 US$ 33,000/t, Sn US$ 22,000/t, Cu US$ 7,000/t. Recovery assumptions: total WO3 recovery 72%, total Sn recovery 68% & total Cu recovery 85% and payability assumptions of 81%, 90% and 90% respectively.
2018 High Grade Exploration Target
SRK UK also identified a high-grade exploration target within the SVS of 4-6 Mt with an estimated grade between 0.9% SnEq and 1.3% SnEq.
It should be noted that this exploration target is conceptual in nature, that there has been insufficient exploration to define a mineral resource within this target volume and that it is uncertain if further exploration will result in the determination of a mineral resource.
Cross section showing Inferred Resource (SVS High Grade Zones) & Exploration Target
A process plant engineering and surface infrastructure study was completed by Fairport Engineering in April 2018. This study included capital and operating cost estimates for the processing plant and mine surface infrastructure.
A consulting metallurgist, experienced in processing Cornish ores, has been retained by CRL to guide future metallurgical testwork.
Consultants Mining One completed a mining study in May 2018, which utilised the 2018 resource to produce a potential scoping-level mine design, life-of-mine schedule and mining capital and operating cost estimates.
An economic assessment of the project based on the 2018 processing, surface infrastructure and mining studies has been carried out by CRL and has shown that the Redmoor project is economically attractive, especially if the size of the resource can be increased.
2018 Drilling Program by Cornwall Resources
CRL will commence a fully funded 2018 Phase 1 drilling program (4,000 m) in June 2018 which will focus on extending the high-grade resource at Redmoor and aim to add a significant portion of the 4-6Mt exploration target to the resource.
The grade of the inferred resource increases with depth; it is hoped that the 2018 drilling program, focused on the Exploration Target which deeper than the existing resource may also increase the overall grade of the resource.
A general permitted development order (GPDO) has been obtained for the drilling programme. Continuing consultation with landowners, local community, local councils and other key stakeholders will form an integral part of the drilling program planning and implementation.
Grade of Inferred Resource Increasing with Depth
The Redmoor High Grade Resource is in the world’s top five highest grade tin-tungsten projects (SnEq Basis) and the top 3 new projects.
The Redmoor Inferred Resource has 45,000 tonnes of contained tin equivalent and the Exploration Target has the potential to increase this to 100,000 tonnes via further drilling planned for 2018. If successful, Redmoor will become a world-class project in terms of contained metal.