Overview
Status | Care and Maintenance |
Mine Type | Open Pit |
Commodities |
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Mining Method |
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Processing |
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Mining commenced in early 2015 and fresh graphitic rock was extracted from the open pit. Despite the Woxna project producing graphite to grade and recovery specifications, the global flake graphite became increasingly challenging during 2015, with prices falling to four year lows of less than US$700/tonne. Given these weakening conditions, in July 2015 the Board elected to halt production until graphite prices recover.
The Woxna graphite mine is not currently operating and will not commence meaningful production until market conditions warrant. The Company is currently pursuing opportunities to produce higher value specialty products such as high purity graphite for lithium ion batteries and other specialty end uses. |
Latest News | Leading Edge Materials Closes Private Placement Financing December 31, 2019 |
Source:
p. 7, 15
Summary:
Graphite is developed as an accessory mineral as laminated aggregates dispersed through schistose and siliceous metamorphic rocks. Graphite is an opaque mineral with six-sided form and crystallises in the hexagonal system with rhombohedral symmetry. It has a perfect basal cleavage and thus presents as flat flakes. These have a metallic lustre. Graphite is found as both flakes (>70µm) and a finer grained amorphous, microcrystalline type. Graphite has a dark streak and is visually obvious in core.
At Woxna, the lattermost is the dominant type, associated with prominent pegmatite intrusions that are interpreted to be the heat source during contact metamorphism. The pegmatite intrusions comprise quartz, orthoclase and phlogopite and intrude a metamorphosed, highly strained stratigraphic succession dominated by sedimentary and volcaniclastic protolithologies, which have undergone later brittle fracturing.
The graphite deposits occur beneath a thin blanket of Quaternary age moraine deposits. The graphite and minor associated pyrrhotite are excellent conductors that allow for prospecting using geophysical methods.
Graphite mineralization occurs in prehnite bearing meta-tuffs, garnetiferous meta argillites and pegmatitic gneiss in at least three discontinuous, stratiform graphite pyrrhotite horizons.
Summary:
The property has a thin overburden layer and near surface mineral resource. Consequently the conventional open pit mining method previously used at Kringelgruvan continues to be the most suitable and economic method to restart mining. The Kringelgruvan open pit mining method, which includes drilling, blasting, loading, and hauling, is designed for multiple open pit phases throughout the LOM. Drilling and blasting will be required on all of the mineral resource and waste rock. Drilling is planned to be performed using conventional downthe-hole hammer rigs capable of single pass drilling. Blasting will use commercial bulk explosive (emulsion) with down-hole delay initiation. A hydraulic shovel will load 40 tonne off-highway haul trucks.
Flow Sheet:
Summary:
The crushing was carried out by a contactor and the equipment is no longer available. Options for the crusher include purchasing and operating or contracting out the crushing operation. GBM proposes that the crushing plant is owned and operated by Woxna.
The design is based on crushing test work by Metso in 2012. Metso reported that the sample is abrasive but the crushability is easy. The slippery low-friction nature of the graphite in the material has been taken into account in selecting the liners. The product from this plant will be 80 % passing 6.35 mm to maximise the throughput of the rod mill.
The ROM material is fed at 70 t/h directly into the ROM bin by a mine haulage truck or from the ROM stockpile by a front end loader. The ROM has a top size of 600 mm. The ROM is screened by a vibrating grizzly to remove minus 60 mm particles. The oversize is fed into a jaw crusher where it is crushed to minus 88 mm. The grizzly undersize and crushed products are transf ........

Reserves at October 31, 2018:
Category | Tonnage | Commodity | Grade |
Measured
|
1 Mt
|
Graphite
|
10.7 %
|
Indicated
|
7.7 Mt
|
Graphite
|
9.3 %
|
Inferred
|
1.9 Mt
|
Graphite
|
8.5 %
|
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