The East Kemptville deposit is a greisen-hosted Sn-Cu-Zn-Ag-In deposit with the alteration and mineralization predominantly affecting the East Kemptville leucogranite (EKL). Three major lithologies (besides overburden) are recognized for the East Kemptville deposit. They are:
1. Leucogranite (EKL) intrusive which is primary host of the mineralization.
2. Within the Baby Zone, a contact zone which is a mineralized igneous breccia containing both metasediment and granite clasts.
3. Metasedimentary rock consisting of interbedded psammites and pelites.

Tin and base metal (Zn-Cu-Ag-W) mineralization within the deposit is primarily fine to medium-grained and is associated with northeast-trending, sub-vertical and zoned, quartztopaz, sulphide-bearing greisens, veins, and stockworks that occur primarily in the sericitesilica-topaz altered portions of the leucogranite meet the roof zone in contact with surrounding metasediments.

In many respects, the geometry of the mineralization over the areal extent of the deposit appears akin to a series of closely spaced jellyfish where the bodies represent wider zones of 51 intense fracturing and coalescing greisens near the top of the intrusion and where the tentacles represent narrower, higher-grade feeders or root zones. A structural control on the emplacement of the mineralization may help explain why some thicker (20-40 m) portions of the deposit occur at greater depths and why some thinner zones (2-5 m) occur at higher levels (i.e., northern portion of Main Pit). In general, the zones below the current pit appear to be thinning and are of higher grade.

The overall gross dimensions of the original potential economic mineralization at the Main and Baby Zones based on a cut-off grade of approximately 0.05% Sn are in the order of 1,500 m long, 350 m wide and 75 m to 150 m deep. Most of this volume is represented by the larger, Main Zone, which has been further subdivided into three subzones termed the Western Flank and South and North Extension Zones. The smaller and discrete Baby Zone occurs a few hundred metres southwest of the Main Zone within what is believed to be a structurally controlled, satellite intrusion. The intrusion hosting the Baby Zone is in the order of 250 m long and 50 m to 75 m wide, but may be continuous with that of the Main Zone at depth through the South Extension Zone.

Higher grade, thicker, mineralization in the Baby Zone is focused along its structurally controlled, southeastern contact with the metasediments and along an interpreted fault that continues northeastward through the Main Zone. Here, potentially economic mineralization reaches tens of metres in thickness and grades appear to average over 0.20% Sn, 0.30% Zn and 0.10% Cu.

The Main Zone mineralization is closely associated with ductile zones and greisens are predominantly restricted to fractures whereas the Baby Zone displays brittle deformation and has pervasive greisens below the wallrock contact.

Mineralization between the Main Zone and the Baby Pit is referred to as the Southwestern Extension of the Main Zone and is not exposed at surface but intersected in drilling.

The mining will re-start as a continuation of the historic open pit operation using a conventional drill and blast process and conventional truck and shovel methods for material movement. Mill feed will be hauled to a small (24 h) stockpile and then reclaimed into the crusher rock box by a front-end loader. The mill treatment rate is set at 2,208 t/d (806,000 t/y) starting initially using only stockpiled material, which will then be supplemented by new feed mined from the Baby Zone Pit during production Years 2 and 3. Thereafter, mining will take place from the southern portion of the Main Zone Pit in Years 3 through 7, followed by production from two pits located in the northern portion of the Main Pit Zone in Years 7 through 14, after which the operation will be fed with the remainder of the legacy stockpile through Years 15 to 19. During Years 2 through 14 when the majority of mill feed is sourced from the pits, approximately 6 weeks’ worth of material will be scheduled from the legacy pile in order to (a) incrementally reduce the environmental liability and (b) maintain mill productivity in the event significant operational delays are encountered in the mine.

Two rotated resource block models were prepared by Avalon at different block resolutions (6 m x 6 m x 6 m for the Baby Zone, and 24 m x 24 m x 12 m for the Main Zone). The two models were merged to create a single functional model suitable for mine planning and pit optimization at a resolution of 6 m x 6 m x 6 m.

Key milestones for the conceptual Project development are described below:

Year -1: Dewatering of the Baby Pit and Main Pit begins, along with site preparation for construction of plant.

Year 1: Final dewatering and removal of sludge in the Baby Pit takes place during Q1 and Q2. Shipment from the legacy stockpile begins in Q3, with process tailings directed to the TMF. Dewatering of the Main Pit continues and will carry over into the first month of Year 2.

Year 2: Mine operations in the Baby Pit begin supplemented by feed from the legacy stockpile. Waste rock is shipped to its final destination to the west of Main Pit South and tailings are directed to the TMF. Any overburden material suitable for use in future revegetation work will be set aside.

Year 3: Baby Pit production ceases and Main Pit South mining begins, supplemented with legacy stockpile feed. Waste rock from both pits is shipped to Waste Zone A and process tailings are sent to the TMF.

Year 4-6: Production feed is sourced from Main Pit South, supplemented with the RAL legacy stockpile. Waste rock is shipped to Waste Zone A. Once the TMF capacity is reached in the last quarter of Year 4, tailings will be directed to the Baby Pit. Beginning in Year 6, mill feed from the Main Pit will be processed through a sulphide flotation circuit to produce clean tailings to cap the TMF.

Year 7: Main Pit South production ceases and Main Pit West mining begins, supplemented with legacy stockpile feed. A portion of the waste rock from Main Pit West will be temporarily staged as required to create a fill ramp in Year 9 to haul mill feed excavated from the lower benches. Sulphide tailings are directed to the Baby Pit, with low-sulphide tailings directed to capping operations.

Year 8-10: Production feed sourced from Main Pit West is supplemented with the RAL legacy stockpile. Stockpiled waste rock from the upper benches of Main Pit West is used to construct a fill ramp needed to haul mill feed from the lower benches in year 9 and 10. Remaining waste in is shipped to the final lift of Waste Zone A and the first lift (70 m elevation) of Waste Zone C. Low-sulphide tailings are directed to capping operations and sulphide tailings are deposited in the Main Pit South repository.

Year 11-14: Production feed is sourced from Main Pit North, supplemented with the RAL legacy stockpile. Waste rock is shipped to Waste Zone C and D. Sulphide tailings continue to be directed to Main Pit South, with Year 11 being the final year of lowsulphide tailings production used for surface capping of the TMF. In Year 12, additional capacity in Main Pit South becomes available that will be sufficient for tailings deposition through Year 13. In Year 14, tailings deposition will be directed to the Main Pit West area.

Year 15-19: Mill production comes from the RAL stockpile for the remainder of the Project life. Tailings deposition continues in Main Pit West and Main Pit South areas through Year 16. Beginning in Year 17, tailings are directed to the Main Pit North pit area, after which tailings will continue to be deposited in the Main Pit for the remainder of the schedule. If evenly distributed, the estimated tailings volume in the Main Pit will approach an elevation of 87.5 m, leaving approximately 0.9 Mm3 of additional capacity that may be used to reach the final allowable fill elevation of 90.5 m.

The 100 tonne per hour operation to treat the mineral resources at East Kemptville consists of several conventional processes to produce a tin concentrate. The plant feed undergoes crushing in a three staged crushing circuit, milling and classification, and is then put through a series of gravity circuits using high-speed centrifugal concentrators (HSCCs), magnetic separation and flotation to remove the metal sulphide before going through a series of shaking tables.

Crushing Circuit.
The crushing circuit consists of a three staged crushing circuit and a series of screens for classification and magnets for tramp iron removal. Run-of-mine (ROM) material is fed at a rate of 200 t/h to a vibrating grizzly feeder (with 50 mm openings) by a front-end loader. Material greater than 400 mm is retained ahead of this feeder by a static grizzly screen and broken with a hydraulic rock breaker.

Material coarser than 50 mm is fed to a jaw crusher and then combined with feed ........