The True North’s Aapplauttoq Ruby Project’s Process Plant consists of the following primary sub-processes:
- Crushing (Primary & Secondary)
- Dense Media Separation (DMS)
- Optical Sorting
The process plant, as proposed, is scheduled to operate 1 – 12 hour shift per day for 224 days each year between the months of April through November. Design parameters allow for a plant utilization of 90%.
All Sub-processes described will be housed in a single “Process Building” which is a purpose built steel structure housing not only the sub-process facilities but as well the Office / Security structure and all required electrical and control facilities. The Process Building will be located adjacent to the project maintenance facility and in close proximity to the open pit. The Process Building will be heated and ventilated as required to allow for personnel comfort and process operations.
The Crushing facility consists of a Primary Jaw Crusher and Secondary Cone Crusher. Associated belt conveyors provide materials handling and allow for the movement of ore between the crushing units. The Primary Jaw Crusher accepts the Run-of-Mine (ROM) ore delivered from the project pit. Ore is transferred into the Jaw Crusher using a Front-end Loader. ROM ore is delivered at a nominal size of 550mm and below. After processing through the Jaw Crusher nominal ore particle size is reduced to 60mm and below. Jaw Crusher product is delivered to the Scrubbing facilities Feed Bin via belt conveyor.
The Secondary Cone Crusher accepts screened material from the Scrubbing facilities Scrubber Discharge Screen. Incoming ore is delivered to the Cone Crusher via Belt Conveyor the Cone Crusher reduces the incoming material from a size of +20mm to a discharge material size of between 20mm and below. Product from the Cone Crusher reports to the Scrubber Feed Bin.
Crushed ore is delivered to the process Scrubber which washes and cleans the incoming ore and delivers the product to a Scrubber Discharge Screen. The Discharge Screen is a horizontal vibrating 3 deck screen which separates the ore into 3 size fractions. +20mm, -20mm to +1.7mm and -1.7mm. The +20mm material is delivered to the Secondary Cone Crusher. The -20mm to +1.7mm is delivered to the DMS Facility via a mechanical conveying system and the -1.7mm is discharged into a collection Pump Box and treated as tailings material. This tailings material is pumped to the project’s Tailings Storage Facility via centrifugal pumps. A “Hand Pick” area is part of the Scrubbing process and allows for a visual inspection of the +20mm material by project personnel. This visual inspection allows for large lumps of Corundum to be physically removed from the process stream which, if delivered to the Secondary Crushing, would possibly result in destruction of larger product quality fragments.
Dense Media Separation (“DMS”)
The DMS facility is a “wet” process, the purpose which is to separate the corundum bearing material from gangue. The Milled or atomized Ferro-Silicon (FeSi) powder will be mixed with process water to produce slurry with a bulk density of approximately 2.7 SG. This FeSi slurry will then be mixed with the crushed and scrubbed ore and pumped to a cyclone separator. The Cyclone will provide material separation, producing a “Heavy” or “Sinks” stream and a “Light” or “Floats” stream. Sinks material including corundum will report to the cyclone underflow and the floats material will report to the cyclone overflow. Float material will then be discarded as tailings material and pumped to the project’s Tailings Storage Facility via centrifugal pumps. The sink material will be collected, dried and passed through a magnetic separator unit, where the FeSi slurry is removed from the product stream. The non-magnetic concentrate is then conveyed to the Optical Sorting facility.
The incoming product is received from the DMS facility and dried utilizing an infrared dryer and is then sorted into 3 size fractions using a Vibrating Mechanical Screen (+10mm, -10mm to 4mm and -4mm to +1.7mm). Each size fraction will be stored in an individual surge bin upstream of the Optical Sorter and then processed independently through the Optical Sorter. The Optical Sorting process utilizes a series of cameras to identify the potential corundum material from the product stream. Once identified, a burst of compressed air separates the identified stone from the product stream. In this manner the incoming product stream is then separated into “Concentrate” or corundum bearing material and “Rejects” material the latter which is expected to contain minimal or no corundum material content. The Concentrate and Rejects stream will be collected into storage containers and stored within the Process Building. Concentrate material will then be transported to True North Gem’s Sorting facility in Nuuk, Greenland while the Rejects are stored onsite for potential future re-processing.
To support the primary processes, services are required. Electrical Feed and Distribution, Compressed air and Process water are all required for the operation of the Primary Sub-Processes previously described. Incoming electrical feed will be obtained from the overall plant site power station and report to the required control and distribution equipment. Air compressors, located within the Process Plant, will provide compressed air as required for process and maintenance operations. Process water is delivered from site services and stored within a Process Water Tank for distribution as required for process and maintenance operations. Process water distribution will be through the use of electrically powered water pumps.