"What we're seeing in the response to our survey is real pessimism about that," he said.
But, miners would not cancel projects that they'd already committed to, he added.
The findings come a week after a Deloitte Access Economics report warned that the mining boom would peak in 2014 and as the thermal coal price fell to US$90 (A$86.87) per tonne and the iron spot price dropped to a fresh low of US$118 (A$113.89) per tonne.
The Mining Business Outlook cited increased costs and tough conditions as the main factors driving mining investment caution, followed by volatile prices and labour shortages.
Mineral deposits which became viable over the past decade due to higher commodity prices could now become uneconomic, Hand said.
While iron ore prices appeared to be stable for now, albeit at a lower level, thermal coal prices were in free fall as some producers considered ceasing production altogether.
"Thermal coal producers are not talking about investment, they're beginning to talk about whether mines will continue to operate," Hand said.
Still, the outlook for iron ore and coking coal remained bright as the rate of industrialisation and steel production continued to motor along in China.
Hand cautioned that the price of thermal coal had fallen significantly since the survey of 55 mining leaders was taken six weeks ago.
Only two per cent of mining leaders said the carbon tax was contributing to caution and more than half of respondents said they had no strategy for dealing with the skills shortage.
-AAP