The Wolfram Camp deposit is a quartz-rich pipe-like type deposit, with major element zoning around the pipes (Plimer, 1974). Similar to other pipe-like Mo- W-Bi(+/-Sn) deposits in the Tasman Geosyncline of Eastern Australia, it is hosted in the greisen altered margin and roof zone of a granite mass. Quartz greisens commonly form a rim of several metres wide around quartz pipes, with variable and generally lower grade mineralisation.

The Wolfram Camp Mineral Field is dominated by the Ootann Supersuite granite intrusives and related greisen alteration and mineralisation. Greisens are apparently developed at the upper contacts of intrusives usually capping apophyses, where late stage (post intrusive) gases and volatiles naturally accumulated, and are in contact with overlying hosts, in this case the sediments and volcanics of the Hodgkinson Formation.

Alteration and mineralisation are considered to be related to a post intrusion (or very late stage) aqueous mineralising phase or phases, which produces a greisen. The mineralisation consists of erratic pods, pipes and veins, in which the majority of sulphide, wolframite and molybdenite is contained, scattered throughout the greisen zone, over a width of ~50 m. The greisen extends up to the contact but not into the host rocks.

Morton and Ridgway (1944) noted that in most of the pipes mined to that date wolframite predominated whilst in some instances (Mulligan, McIntyre, Nil Desperandum) molybdenite was the main mineral. In all cases, however, wolframite, molybdenite and bismuth were all present. In most cases it had been noted that the rare metals crystallised separately but intergrowths involving all three were fairly common. They also reported the characteristic development of vugs in the pipes, ranging from “inches to a few feet across”. Occasionally these vugs occupied the full section of the pipe for many feet. The largest vug encountered to that date was in the Enterprise (German Bill) mine with reported dimensions of 20m by 10m by 7m. These vugs were more or less filled with quartz crystals and loose clayey and sericitic material containing a considerable number of minerals including the rare metals.

Underground sampling, mining records and drill results indicate an overall metal ratio of 10 W: 3:5 Mo: 1 Bi. The other sulphide minerals present in the mineralised zone are predominantly arsenopyrite, pyrrhotite and pyrite with trace chalcopyrite, sphalerite and galena. In total these sulphides occur less than the Mo content. The wolframite from Wolfram Camp tends towards the more iron rich variety ferberite (FeWO4) as opposed to the more manganese-rich variety, huebnerite (MnWO4). Mineralogical work undertaken by JKTech Pty Limited (2006 and 2007), on behalf of QOL, identified the following additional minerals in samples carrying low grade mineralisation within quartz greisen and granite samples:-albite; apatite; chlorite: euxenite; fluorite; MnFe oxides; monazite; orthoclase; rutile; sericite; thorite; Ti-magnetite; xenotime; and zircon.

Pipes have been historically the more important economically; they characteristically dip towards the contact and a few were reported to reach the contact and follow it. The course, size and shape of pipes changes abruptly. Pipes with maximum dimensions of as much as 14m x 9m (Murphy-Geaney) are mentioned but any with a diameter of >1.5m were considered good working size. Mined pipes have ranged from less than 1m in diameter to 15m by 10m in plan, and have down-plunge lengths often exceeding 100m. The pipes comprise predominantly glassy white quartz with shoots containing coarse patches of wolframite and molybdenite. The overall known extent of the mineralised pipes at Wolfram Camp covers a strike length of approximately 800m and a depth of approximately 170m. The average width of the zone containing the mineralised pipes is approximately 85m.

The current open cut is approximately 800m along strike.In general the pit is advanced with benches extended out to the design pit shell on the north-south sides, and is deepened in 3-4 sectors along strike.

Drilling and blasting will be carried out by a specialist D&B contractor.Blasts are planned over 5m bench heights,with combined ore and waste partitions.The individual models determined from GC drilling are used to delineate different categories of material for mining, based on cut-off levels of 0.07, 0.12 and 0.3% WO3.Separate models for each blast area also built up.

Blastholes, 89mm in diameter, are drilled on 2.7 x 2.4 m pattern.Plastic hoses are placed in high grade holes,which are not blasted.This helps against excessive fragmentation of wolframite, and the hoses provide an estimate of blast displacement.All blasting generally uses ANFO. Subsequent to blasting, the positions of the plastic hoses are re-surveyed, and the original ore/waste delineations are modified according to the measured displacements, as well as by visual assessment by geologists.Different colour ribbons are used to demarcate the different ore/waste categories.

Digging of material is done with a backhoe excavator, sitting on top of the broken muckpile, loading 40t trucks.Digging is done in 3 vertical passes: the first for the heave above the original bench floor, the second for the 0-2.5m depth cut and the third for the 2.5-5m depth cut.Ribbons are marked up individually for each cut prior to
mining,based on the blast displacements at the top of each cut.Any additional high grade material spotted visually by geologists is also mined and stockpiled separately.

Clay and topsoil overburden from the mine is stockpiled separate from other waste dumps, for use on closure for rehabilitation.Waste and mineralised waste loads are hauled to stockpiles, and ore is trucked to the ROM pad adjacent the processing facilities.Mineralised waste is either stockpiled or sent to the ROM pad and crushed.

The mineralised waste stockpile is then screened, with <15mm material being sent to the mill, 15-50mm material is sent to the ore sorter,and >50mm material is sent to the crusher as required. Mined tonnages are reconciled against monthly stockpile surveys and these in turn are used to reconcile against the short-term planning block
model.

The process plant is primarily based on gravimetric separation, aimed at recovering a high grade wolframite concentrate. During 2013 it was able to crush 369kt of material and (after ore- sorting) process 259kt of ore, with an average feed grade of 0.25% WO3. With the planned processing improvements it is anticipated that the processing plant recovery will be 71%; and allow a mill capacity of over 518 ktpa.

The design focus for recent updates to the plant process has been to improve the recovery of wolframite by minimising over-grinding of the ore. This will be achieved by increasing the number of ore crushing and screening stages, thereby improving the control of the grinding process. By removing the ball mill (as used previously) and using instead additional cone crushers, it is planned to avoid generating excessive quantities of ultra-fines. This is anticipated to significantly increase the recovery of wolframite in the gravimetric circuit and reduce operational costs.

The fine and coarse fractions pass onto two parallel banks of triple start spiral classifiers and from there onto Wilfley shaking tables. Recoveries from the tables have been recently further improved with the use of flotation frames with Xanthate to assist in sulphide removal.

A series of plant upgrades have occurred since May 2015, lifting the recovery. The upgrade provided with the installation of more10 Wilfley shaking tables and a Hydrosizer to provide separation of sizes through the middlings from tables to improve recovery.

Prior to 2014, material was also passed through a flotation circuit to produce molybdenite concentrate. This equipment is still in place, but has been by-passed since the end of 2013, as it was deemed uneconomic at that time.

The concentrate from the shaking tables is subjected to batch flotation to reduce the fine sulfide content. The sulphide reduced concentrate is dried and cooled.

The accepted material is then transferred to the dressing plant. Here the material goes through a rotary diesel dryer, and from there onto a rare earth roll (RER) magnetic separator. The material is passed through the RER three times. The rejects from the RER, containing scheelite, are currently stored, but will be processed in the future with regrinding and flotation. The RER accepts are split into 3 streams. One stream with relatively high iron is passed through an electromagnetic (EM) unit at low magnetic settings. Low Fe material from the EM is blended back with the accepts from the RER. The high Fe material is retained and blended back when possible. The other 2 streams from the RER are bagged and assayed. Any material with high uranium and thorium (U+Th) is separated, and blended to allow the sale of acceptable concentrates.

Concentrate grades are typically 63% WO3. This final saleable concentrate is bagged (weighed and sampled) and transported by semi-trailer to Brisbane. Once checks are finalised, the concentrate is loaded into sea containers and shipped direct from Brisbane to the port of New York in the USA. Sailing time is approximately 6 weeks, with sail schedules every 2 weeks.