The tungsten component of the ore would be refined into an intermediate product ammonium paratungstate (APT) for shipment.
The operator says that after closure, the open pit, which will be 2 km2 in area and 300–330 metres deep, will be allowed to fill with rain water.
"[6] The tailings storage facility will not be drained or filled after closure but will remain as open water.
After the 2014 catastrophic failure of the Mount Polley tailings dam in the province of British Columbia, Canada, the government-appointed Expert Panel which reviewed the incident found that since 1969, of the province's approximately 100 tailings dams, 7 had experienced major failure.
To in essence assert that 'my engineering' could not possibly fail, in light of existing statistics, is arrogantly assuming that it is always the other guy (or gal) that will make a mistake -- but not me.
R Allen Curry, a professor of biology at the University of New Brunswick, commented as follows: "I respect that the engineers can design a well-built dam that has a low probability of failure under normal operating conditions.
However, the statistics on TSFs are indisputable – the proponent will fail to contain their water.... [A]ssuming a mine life of 27 years and the current empirical rate of 1 [failure sic.]
Pleasant was a tin and tungsten mine located 100 km south of Sisson; its tailings dam failed in 1998.