There's concern over drug use in mines.
Random drug testing at Solid Energy's four mines in the year to June caught 45 workers.
The majority tested positive for cannabis or synthetic cannabinoids, while three were found to have used methamphetamine.
EPMU spokesman Ged O'Connell says the results aren't good enough.
He says any evidence of drug taking is disappointing and unacceptable.
Mr O'Connell says it shows a different regime needs to be put in place, as the current one clearly isn't working.
He says having immediate checks before the shifts start would be much better than random tests, which he says are retrospective.
Ged O'Connell says health and safety in the workplace is far more important than finding out two or three days later.\
Photo: NZ Herald