Licences and Overview
Stellar holds a portfolio of tin projects in the West Coast of Tasmania which enjoy an enviable location within the well-established mining district on the West Coast of Tasmania with a competitive market for services, mining and processing inputs and labour, access to nearby water and power, and to the port of Burnie 150km to the north for export of concentrate.
Location of Stellar’s Tin Projects in the West Coast of Tasmania
Stellar holds the following tin licenses in the West Coast of Tasmania near the historic mining town of Zeehan:
- Heemskirk Tin Mining Lease (ML2023P/M) containing 3 of the 4 Heemskirk Tin Project deposits (Queen Hill, Severn and Montana) and the proposed site for the Heemskirk Tin Project processing plant near Zeehan.
- Heemskirk Tailings Storage Mining Lease (ML2M/2014) over the tailings storage site for the Heemskirk Tin Project
- Heemskirk Tailings Pipeline Route Mining Lease (ML2040P/M) over the tailings pipeline route for the Heemskirk Tin Project
- St Dizier Tin Mining Lease (ML10M/2017) over the St Dizier satellite open-pit tin deposit located 20km to the northwest of Zeehan
- Montana Flats Exploration License (EL13/2018) containing the Oonah deposit, the fourth of the 4 Heemskirk Tin project deposits, along with significant exploration potential and a number of historic lead and zinc mines
- Mount Razorback Exploration License (EL11/2017) containing the historic Razorback Mine, Razorback Mine Tin Exploration Target (a satellite project located 8km east of Zeehan), Razorback Tailings and significant exploration potential
Stellar holds the best Portfolio of Tin Assets in Australia with Secure ML’s over Heemskirk and St Dizier and a large EL package providing further upside and flexibility.
Location of Stellar’s Tin Licences around Zeehan, Tasmania
Stellar’s flagship Heemskirk Tin Project includes the Queen Hill, Severn, Montana and Oonah tin deposits.
The Heemskirk Tin Project Scoping Study completed in October 2019 is based on development of an underground mine, processing plant, tailings storage facility and surface infrastructure to mine ~ 350ktpa ore from the Queen Hill and Severn tin deposits (2 of the 4 Heemskirk Tin Project deposits) over a 10 year mine-life. The Scoping Study also included open-pit mining of the St Dizier satellite deposit and trucking to the processing plant at Heemskirk during the final year (year 11) of the project.
Geology and Exploration History
St Dizier is a satellite open-pit tin deposit located 20km to the northwest of Zeehan. St Dizier is a tin skarn, formed by metasomatic alteration of an original dolomite unit by tin bearing fluids emanating from the Heemskirk Granite. Much of the dolomite is altered to serpentine-magnetite-calc-silicate rock flanked by shales to the south and quartzites to the north. The total meta-sediment package has the form of an east-west trending, vertically dipping roof pendant surrounded by Heemskirk Granite. The skarn consists of magnetite-serpentinite-cassiterite-schoenfliesite-scheelite-bismuthinite. Tin mineralisation is zoned with dominantly cassiterite in the west and increasing amounts of schoenfliesite and other tin species to the east.
43 historic diamond drill holes for 7,309m have been completed at St Dizier over a number of campaigns by different operators. Stellar has completed a further 3 confirmatory diamond drill holes for 317m at St Dizier
St Dizier Interpretive Geology and Drilling
Plan View of St Dizier Geology
The Indicated Resource at St Dizier includes the West and Central Lodes. The bodies crop-out at the surface and strike east-west over a distance of 400m. They dip vertically to a depth of 200m from the surface (in the case of Central) and vary in width from 3m to 40m. Higher tin grades occur between the surface and a depth of 70m in the Central Lode and grades are higher nearer to the surface making the deposit attractive as a potential low-cost open pit development. The smaller Western Lode could also potentially be considered for open pit mining but was not included in the 2019 Scoping Study.
Cross-Section 345,150mE, Central Lode, St Dizier
A total Indicated and Inferred Mineral Resource for St Dizier of 2.3mt @ 0.61% Sn (13,786t of contained tin) at a cut-off grade of 0.3% Sn has been defined in accordance with the JORC Code 2012 by technical consultant, Resource and Exploration Geology, in March 2014. The Indicated component of the resource is 1.2mt grading 0.69% tin, 87% of which is in the form of cassiterite. There has been no material change to assumptions since the resource estimate was completed in 2014.
St Dizier Mineral Resource Statement (JORC 2012), March 2014
A mining study on the St Dizier Deposit completed by Polberro Consulting in July 2015 forms the basis of the mining assumptions used in the Hemskirk Tin Project 2019 Scoping Study. The Polberro St Dizier mining study included; pit optimisation, open pit mine design, consideration of geotechnical factors, bench geometry, mine production rate and mining operating and capital costs.
The Polberro St Dizier mining study focused purely on part of the Central Lode Indicated Resource and determined that an open pit mining method which is well suited to the Central Lode mineralisation as it crops out at the surface, has its highest grades within 50m of the surface, occurs as multiple lenses over widths of 3m to 40m and is surrounded by relatively competent wall rocks. It is also the lowest cost mining method available for the style of mineralisation.
Key results from the Polberro St Dizier mining study, used in the 2019 Scoping Study include:
- In-pit diluted indicated mineral resource of 409,179t @ 0.90% Sn with an average strip ratio of 4.7:1 after application of 10% mining dilution and 95% mining recovery factors
- 100% Indicated Mineral Resource
- Mining capital costs of A$3.3m for drainage diversion, pit development and construction of a waste which can be completed within 3 months
- Mine closure capital cost of A$0.5m
- Contractor operated mining costs estimated at A$26/t ore mined inclusive of waste removal,
- Trucking cost of A$5/t for trucking St Dizier ore a distance of 20km to the processing plant at Heemskirk
- The accuracy of the mining operating cost and capital cost estimates was ±35%
The Heemskirk Tin Project 2019 Scoping Study includes mining from the St Dizier satellite tin deposit which will be mined as an open pit mine and processed in the Heemskirk plant during the last year of the project.
Long Projection St Dizier Tin Deposit
St Dizier ore is similar in complexity to that at Upper Queen Hill. Stage 1 test work on diamond drill core from St Dizier has been undertaken by ALS Metallurgical Laboratory in Burnie and supervised by Worley Parsons. The test work showed the following outcomes:
- Mineralisation in the sample was quite variable and provides a wide range of responses
- High tin losses to magnetite, slime and tin float tails resulted in overall recovery of 43%
- Gravity concentrate tin grade of 55% is possible through pre-gravity sulphur removal
- Tin float grade could be significantly upgraded by optimising deslime, talc management and acid leaching of concentrate
- Stage 2 optimisation has the potential to increase tin recovery up to 50% into a 50% tin in concentrate product
The Montana Flats Exploration License EL13/2018 was granted to Stellar in August 2018 after winning a competitive tender process run by Mineral Resources Tasmania for the license. he Montana Flats EL13/2018 adds the Oonah tin deposit, the fourth of the known Heemskirk Tin Project deposits and also importantly, adds the northwest trending structural corridor along which all tin deposits and major historical silver mines lie and greatly enhancing the exploration potential of the Heemskirk Tin Project.
Montana Flats is a highly mineralised tenement that hosts similar geology and mineralisation to Stellar’s flagship Heemskirk Tin Project (ML2023P/M). Importantly, the Queen Hill, Severn and Montana tin deposits of Heemskirk lie within dilation zones associated with major northwest trending structures identified as the Oonah and Montana Faults. These and associated faults extend well into EL13/2018 where they host a number of historical silver/lead mines. Zeehan Western, the second largest silver/lead producer in the Zeehan field is associated with the Montana Fault and the Oonah silver mine, the fourth largest producer, lies on the Oonah Fault. The Oonah tin resource parallels the silver/lead lode on the Oonah Fault.
Montana Flats EL13/2018 – Interpretative Geology
The style of mineralisation at the historic Razorback Mine is essentially the same as at Renison Mine, located 7km along strike to the north.
The geology of the Razorback Mine is dominated by the Razorback Fault where the Cambrian serpentinite is in faulted contact with the younger Dundas Group Red Lead Conglomerate and Hodge Slate. The Serpentinite has been strongly dolomitized and talc altered within 20-30m of the fault contact. The sequence strikes north-northwest and is near vertically dipping with the fault dip steep east near surface to steep west dipping below 100m depth.
Tin mineralisation is hosted within the talc-carbonate altered serpentinite and the Red Lead Conglomerate where they are adjacent to the Razorback Fault. The mineralised lodes are semi continuous and plunge steeply south within the plane of the fault. Mineralisation consists of semi-massive pyrrhotite with cassiterite, pyrite, arsenopyrite, chalcopyrite, sphalerite and galena.
The lode is wedge shaped with a width of 10-15m at the top (base of pit floor), narrowing to widths of 2-3m at a depth of approximately 100m below the pit floor. The average length of the significant intersections listed in Appendix 1 is 6.4m. The Razorback lode strikes over [200m] and possibly plunges steeply south to over 400m in depth.
Razorback Mine Typical Cross Section 5,363,850mN
Exploration and Mining History
Initial exploration over the Razorback Tin Mine was undertaken from 1958 to 1969 by the Bureau of Mineral Resources and the Tasmanian Mines Department who completed 7 surface diamond drillholes for 528m.
Extensive underground exploration development, 22 underground diamond drillholes (1,009m) and underground bulk sampling was completed over the Razorback Mine by Placer Prospecting Ltd between 1964 and 1966. Placer also completed 16 surface diamond drillholes over the Razorback Mine during this period.
The Razorback Mine was operated as an open pit mine by Minops Pty Ltd from 1975 to 1978 during which time an estimated 180,000 tonnes of ore at ~0.6% Sn was mined and processed by an on-site processing plant and tailings facility.
In 1978 Minops completed a further 7 surface diamond drillholes aimed at locating extensions of the ore to the south of the open cut.
In 1979 a Joint Venture was signed between Minops and CRA Exploration who proceeded to drill 5 deeper surface diamond drillholes over the next few years. In 1982, CRA Exploration decided not to procced further with the project.
In total 35 historic surface diamond drillholes (6,054m) and 22 underground diamond drillholes (1,009m) have been completed over the Razorback Mine between 1958 and 1984.
In 2018, Stellar dug and sampled 3 costeans in the pit floor.
Razorback Mine Long Projection
Razorback Mine Exploration Target
An Exploration Target of 180,000 – 220,000 tonnes @ 0.8 – 1.0% Sn at a cut-off grade of 0.3% Sn has been defined to a depth of 100m below the previously mined Razorback pit floor in accordance with the JORC Code 2012 by technical consultant, Resource and Exploration Geology, in July 2019. There has been no material change to assumptions since the estimate was completed in 2019.
Razorback Mine Exploration Target
It should be noted that this Exploration Target estimate is conceptual in nature. There has been insufficient exploration to define a Mineral Resource in this volume and it is uncertain if further exploration will result in the determination of a Mineral Resource.
Re-development of the Razorback Mine could potentially provide a source of early tin production and cashflow which Stellar plans to study further, after a Mineral Resource is defined.
Most of the historic drilling, which forms the basis of the Razorback Mine Exploration Target, has only tested mineralisation to a depth of ~150m below the current pit floor. Possible extensions to the Razorback Mine orebody were further identified by CRA Exploration in 1979 after drilling 5 deeper holes. Further drilling of deeper extension targets, such as those identified by CRA Exploration in 1979, have the potential to substantially increase the Razorback Mine Exploration Target.
Razorback Fault and Grand Prize Targets
There is potential for discovery of further mineralisation along the Razorback Fault over the 7km of strike length between Razorback and Rension and including the Grand Prize Tin deposit, also within Stellar’s Exploration Licence (EL11/201).
The Grand Prize-Razorback Fault structure is a large mineralizing system. Its proximity to the Pine Hill Granite and the Renison Bell Tin Mine make it highly prospective for structural and replacement style tin-copper deposits.
Broad spaced historic exploration of the Grand Prize Fault suggests it is a large mineralizing system, although possibly sub ore grade at this stage. There are ore grade intercepts within the larger low-grade intercepts suggesting there may be some scope for targeting and modelling of higher-grade zones. There is also the possibility of recovering a copper concentrate adding value to the mineralisation. To put it into perspective, the known mineralizing system covers an area twice that of the Severn deposit at Zeehan and remains open down dip.
Razorback – Grand Prize Fault Structure Geological Plan