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Redmoor


Location & History 

The Redmoor Project is located between the village of Kelly Bray and the small town of Callington in south east Cornwall, United Kingdom, approximately 25km by road from the city and port of Plymouth, and 40km from the recently commissioned 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.

location_and_history

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 at intervals, 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 that mining in the Redmoor Mine, Kelly Bray Mine and Wheal Florence Mine on NAE Redmoor license area produced 574 tonnes of tin, 268 tonnes of WO3, 852 tonnes of copper, 153 tonnes of lead and 9,179 ounces of silver.

Ownership

In October 2012, NAE acquired a 100% interest in the Redmoor Tungsten-Tin Project through an Exploration License and Option Agreement with the owner of mineral rights covering a large area of approximately 23km2 that include the Redmoor Project. The Exploration License was granted for an initial period of 15 years with modest annual payments.

NAE also has the option 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 required and is subject to a 3% Net Smelter Return royalty payable to the mineral right owner once commercial production has commenced.  NAE also has a pre-emptive right over the sale of the mineral rights by the vendor. Surface land access for exploration drilling and mining over part of the Redmoor deposit is also included in these agreements.

Geology

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 mineral containing fluids to be mobilised along fractures and faults in surrounding rocks.  Redmoor is located adjacent to the Kit Hill Granite Intrusion which is historically a source of mineralised fluids and a number of historic mines both within and adjacent to the NAE mineral rights.

At Redmoor, tungsten and tin oxide and other metal sulphide mineralisation occurs both in discrete veins or lodes (eg Johnsons Lode, Great South Lode) and within a zone of numerous closely spaced sub-parallel narrow quartz veins known as the Sheeted Vein System (SVS).

geology

Redmoor 3D View looking East 

 

Previous Exploration, Testwork and Studies

South West Minerals Limited (“SWM”) completed a drilling program at Redmoor between 1980 and 1983 comprising 35 diamond drillholes (totaling 12,146m) to a maximum depth of 600 meters. The SWM drillholes targeted tungsten-tin mineralisation within the Sheeted Vein System (“SVS”) and also within the higher grade Johnsons Lode at Redmoor. The SWM drillholes also intersected the Great South Lode.

The majority of the SWM drillholes were angled holes drilled perpendicular to strike and designed to intersect true thickness of the target lodes. All holes were downhole surveyed. Core was split and assayed for Sn, W, Cu, Pb, Zn, Ag and As in mineralised zones. Sampling intervals were generally 2m length.

Two metallurgical testwork programmes were undertaken on composited samples of crushed diamond drill core by South West Metallurgical Services (SWMS) (Penzance, Cornwall U.K) and by Robertson Research International (RRI) (North Wales).  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

In 2015, NAE completed a detailed review of the metallurgical historic testwork and concluded that Redmoor ore is coarse grained and 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.

Inferred Mineral Resource

In December 2015 SRK UK and NAE completed the following activities resulting in an updated JORC Inferred Mineral Resource and Exploration Target being defined for the Redmoor Project:

  • Review of results of 35 diamond drillholes (totaling 12,146m) completed at Redmoor by South West Minerals Limited (“SWM”) between 1980 and 1983 and of historic mining data
  • Re-validation of the drill hole database including the identification of Johnsons Lode and Great South Lode intersections and separation of these from SVS mineralisation intersections
  • Updated geological interpretation (3D wireframe models) to reflect the above
  • Updated block model and grade interpolation
  • Revised cut-off grade determination to reflect updated metal price forecasts and estimates of operating costs
Description Tonnage (Mt)

WO3

%

Sn

%

Cu

%

WO3Eq

%

SnEq

%

Johnsons Lode 0.8 0.36 0.55 0.78 0.91 1.37
Great South Lode 1.5 0.33 0.50 0.32 0.74 1.10
Sub Total – High Grade 2.3 0.34 0.52 0.48 0.80 1.19
Sheeted Vein System 11.0 0.12 0.14 0.28 0.28 0.42
TOTAL 13.3 0.16 0.21 0.32 0.37 0.56

Redmoor 2015 Inferred Mineral Resource Estimate[1]

[1] Equivalent metal calculation notes; WO3(Eq)% = WO3%*1 + Sn%*0.67 + Cu%*0.24, Sn(Eq)% = Sn%*1 + WO3%*1.50 + Cu%*0.36. Commodity price assumptions: WO3 US$ 37,000/t, Sn US$ 23,500/t, Cu US$ 6,700/t. Recovery assumptions: total WO3 recovery 72%, total Sn recovery 68% & total Cu recovery 85% and payability assumptions of 79%, 87% and 87% respectively.

Exploration Target

In December 2015 SRK UK also identified the following Exploration Targets for the Redmoor Project in addition to the Inferred Mineral Resource:

  • High Grade Exploration Target – SRK has identified an Exploration Target for extensions to the modelled high grade lodes (Johnsons and Great South Lodes) and for other similar lodes identified though historical data and a limited number of drilling intersections of 4Mt to 6Mt with an estimated  grade of between 0.6% WO3Eq (0.9% SnEq) and 1.0% WO3Eq (1.5% SnEq)
  • SVS Exploration Target – SRK has identified an Exploration Target for lateral extensions to the SVS of 3Mt to 4Mt with an estimated grade of between 0.2% WO3Eq (0.3% SnEq) and 0.4% WO3Eq (0.6% SnEq)

It should be noted that this estimate is conceptual in nature and there has been insufficient exploration to define a Mineral Resource and that it is uncertain if further exploration will result in the determination of a Mineral Resource.

exploration_target

Plan View showing Key Mineralised Lodes in the Redmoor Project

 Johnsons Lode is the main lode to have been historically worked within the Redmoor Mine. It is a high grade mineralised vein carrying tungsten, tin and copper that strikes at approximately 80 degrees and dips at approximately 78 degrees to the south.  Johnsons Lode is located to the north of the SVS and intersects the SVS and Great South Lode at depth. The Johnsons Lode Inferred Mineral Resource has a strike length of 920m and a down-dip extent of 340m.

target_2

Johnsons Lode Long Section (looking north)

Great South Lode is a high grade mineralised lode carrying tungsten, tin and copper. It is located directly to the south of the SVS and has not been historically worked. However, a number of development roadways intersected Great South Lode and one drive was developed within Great South Lode for a distance of approximately 125m parallel to Johnsons Lode. Great South Lode strikes approximately 65 degrees and dips at approximately 55 degrees to the north and, as a result, intersects the SVS and Johnsons Lode at depth. The Great South Lode Inferred Mineral Resource has a strike length of up to 510m and a down-dip extent of 620m.

target_3

Great South Lode Long Section (looking north)


Work Program

Exploration Drilling

An exploration program is being developed by NAE with a principal outcome of converting the high grade exploration targets to Inferred Mineral Resources where continuity is demonstrated and also of improving confidence in the Inferred Mineral Resource with a view to enabling the reporting of a first Indicated Mineral Resource for the project. A limited amount of drilling to confirm historic drilling results will also be included. Priorities for the exploration drilling program are to test the following targets:

  1. Mine tailings potential for re-processing. These are shallow, low cost, holes with potential to generate early cash flow if sufficient quantity and grade of tailings with acceptable recoveries can be identified.
  2. Great South Lode & Johnsons Lode depth extensions in particular the interpreted high grade zones
  3. Great South Lode and Johnsons Lode strike extensions to the west of the fault
  4. Kelly Bray Lode extensions along strike and at depth below historic workings
  5. Eastern shallow extensions of Great South Lode, Johnsons Lode and the Sheeted Vein System

The total drilling program will include 30-40 holes with an average depth of around 400m. The program may be phased to focus initially on high grade, high priority targets.

Consultation with landowners, local community, local councils and other key stakeholders will form an integral part of the drilling program planning and implementation.

High Grade Mining Option Study

The Company is currently focused on advancing a high grade mining option for the Redmoor Project. Studies underway include:

  • A mining study has been commenced by technical consultants, Mining One and is expected to be completed in late January 2016. Results to date from the Mining Study have been encouraging, showing that the Redmoor deposit can be mined using a bench stoping and fill underground mining method at relatively low mining costs with 1.5m to 2.0m minimum stope widths.
  • A metallurgical processing review has recently been completed which shows that Redmoor ores can be expected to be processed at low cost with high recoveries.
  • Stand-alone project and toll processing options are being examined for the project.