Perhaps the best way to understand Dalradian’s project is to compare it to a hi-tech, highly regulated, precision-led quarry – only one that is based underground with some processing on the surface.
There are six stages to Dalradian’s approach. The second is ‘processing’.
Unlocking Tyrone’s Precious Metals
Once the narrow veins or seams which contain Curraghinalt’s gold, copper and silver have been mined underground, the next step is to separate the valuable minerals from the extracted rock. This ‘processing’ begins underground before moving to the surface.
One of the project’s guiding principles is to retain or return as much mined barren rock underground as possible. This is environmental good practice, uses less energy, strengthens the mine development and reduces the amount of rock that is stored above ground.
Using a ‘crusher’ underground, the mined rock is broken down into smaller pieces (tennis ball sized or smaller). These crushed rocks are separated from the minerals using a specialised ‘ore sorter’ with sensors to detect pieces containing gold, copper and silver.
To minimize carbon and dust emissions, a covered electric conveyor belt will transfer rock to the surface (this replaces the original proposal which used diesel-fuelled trucks and will, with other measures, reduce fuel consumption by 25%).
The ore goes to the processing building above ground, whilst the remaining rock, devoid of minerals, is either returned underground to backfill spaces created by mining or stored above ground in a ‘Dry Stack Facility’.
The ore enters a two-stage grinding circuit in the processing building. Using SAG and ball mills, the ore is rotated with steel balls and water in large “drums” to mill it into a finer size (similar to sand). It is then sent to a flotation tank.
Using just water and biodegradable substances, the flotation tanks help metallic elements attach to bubbles which float to the top where they are skimmed off to form a mineral concentrate. The concentrate will be shipped overseas to create gold and silver bars and copper sheets.
Thanks to changes which Dalradian introduced in 2019, no cyanide or smelting will be used on site, nor will a hazardous materials licence be needed.
Due to Tyrone’s leadership in designing and manufacturing mining and quarrying equipment, some processing equipment will be sourced locally.