The Red Dog is an open-pit, zinc-lead mining operation by Teck Resources in northern Alaska, US. Producing since 1989, it is considered to be one of the biggest zinc mines in the world.
While the Red Dog deposit was discovered in 1968, Teck Cominco (now Teck Resources) staked the first claim on the property in September 1975 followed by additional exploration and land rights acquisitions under lease from the Alaska Native Corporation (ANC) NANA.
The main construction works on the project were started in 1987, and completed in November 1989, while the mine commenced operations in the same year.
The Red Dog mine produced a total of 552,400 tonnes (t) of zinc and 102,800t of lead in 2019.
Project location and geology
The Red Dog mine is located approximately 145km north of Kotzebue, in the DeLong Mountains north of Noatak, in the western end of the Brooks Range of Northern Alaska. The project area comprises land owned by NANA Regional Corporation.
The Red Dog geology comprises stratabound, massive sulfides, and barren mudstones occurring as multiple, superimposed thrust fault slices, hosted in shale, sedimentary exhalative deposits.
The host rock is characterised as black, siliceous shale and chert of the Ikalukrok unit of the Mississippian to Pennsylvanian Kuna Formation.
The upper ore body is oxidised and the ore textures through the deposit are generally massive, fragmental, chaotic, and veined, with a weak upward enrichment of lead relative to zinc.
Mineralisation and reserves
The Red Dog zinc mine has three deposits namely, the Main, Qanaiyaq, and the Aqqaluk deposits. Mineralisation at the Main deposit occurs in fault slices with the high-grade mineralised zone extending up to 1,600m-long and 975m-wide, with a thickness of up to 135m.
The Qanaiyaq deposit, also known as the old Hilltop orebody, is similar to the Main deposit, occurring as a horizontal klippe with a mineralised zone that is 490m-long, 245m-wide, and up to 100m-thick.
The Aqqaluk ore body occurs north of the Main deposit and is composed primarily of Sphalerite and galena occurring in silica rock, barite, and shale with disseminated, semi-massive to massive sulphides.
The proven and probable mineral reserves at Red Dog were estimated to be 50.9 million tonnes (Mt) grading 12.9% zinc (Zn) and 3.6% lead (Pb), as of December 2019.
Mining operations at Red Dog
The Red Dog zinc-lead mine is an open-pit operation, using the conventional drill, blast, truck, and loader methods.
The main pit has been depleted and the current mining operations are focussed on the Aqqaluk deposit that commenced production in August 2010 with an expected mine-life until 2032.
The Qanaiyaq deposit was brought into production in January 2017 with a planned mine life until 2028.
The Red Dog Mine area also contains the Paalaaq deposit, which is an undeveloped deposit located adjacent to the Aqqaluk deposit.
The mining fleet comprises four excavators and five units of 933k large wheel loaders from Caterpillar supported by four dozers and ten units of 100t 777D/F haul trucks, apart from two graders and three DML drills.
The run-of-the-mine (ROM) ore undergoes crushing in a 1200tph primary gyratory crusher which is backed up by a 700tph jaw crusher.
The crushed ore then undergoes grinding in three semi-autogenous grinding (SAG) mills followed by four ball mills. The regrind facilities comprise three tower-mills for the lead circuit and two Isa mills for the zinc circuit.
The fine ground ore material is then moved to a pre-flotation circuit consisting of six conventional and one Jameson cells to produce zinc and lead solution which is then passed onto the zinc and lead circuits to produce the zinc and lead concentrates.
The obtained concentrates are dewatered, thickened, and filter pressed. The lead filter circuit comprises one Lasta filter press while the zinc filter circuit comprises four Lasta filter presses.
The final concentrate products are transported via the DeLong Mountain Transportation System to the port facilities located on the Chukchi Sea during the shipping season between July to late October. The port also acts as the main import hub for fuel and other mining utilities.
Due to the remote location of the project, the 24.5MW power supply that the Red Dog operation requires is met through an on-site power module comprising eight diesel generators of 5MW capacity each.