Confidence in the mining industry has dropped sharply since last year and only 25 per cent of companies are planning large investments in 2012, a study has found.
According to Newport Consulting's Mining Business Outlook 20 per cent of mining leaders are "very optimistic," down from 57 per cent last year.
Companies planning major investments have also dropped 27 per cent, down from 52 per cent last year.
AAP reports Newport's David Hand said there was "pessimism" about commodity prices staying strong.
"Across the board, we've seen a significant shift in sentiment to the negative in the belief that commodity prices will remain high enough to make future investments pay off," he said.
Hand said while falling commodity prices might make some resources developments unviable companies were not looking to cancel projects that had been already committed.
The report follows rumours BHP Billiton is looking to delay final approval of the Olympic Dam expansion until 2014.
A report by Deloitte Access Economics last week also said the mining boom would only last another two years.