"This is a very important signal for Tasmania - it is open for business with responsible environmental protection and responsible mining development," Gray said.
"These two developments – at Nelson Bay and near Tullah in north-western Tasmania – have the potential to generate significant employment and economic opportunities.
"They will result in millions of dollars of direct and indirect regional business turnover."
Environment minister Mark Butler approved Venture Minerals Limited's Riley hematite mine near Tullah, with strict conditions, after last Wednesday approving Shree Minerals Limited's Nelson Bay River magnetite and hematite mine.
Strict environmental conditions were placed on both projects to reduce any threat to the local environment. The developments had previously received all necessary approvals from the Tasmanian government.
"With an unemployment rate in excess of eight per cent, new opportunities for economic growth in Tasmania are vital," Gray said.
"The total economic benefit of the Nelson Bay project alone is expected to be more than $400 million.
"Shree Minerals has stated its commitment to creating employment opportunities for young Tasmanians, and Venture Minerals has a policy of sourcing local services and goods where possible."
The Nelson Bay River mine will provide employment for ten years, with shipments occurring over the first two years, during which time a processing plant and pit will be developed.
The shorter term Riley Creek mine project involves shipping ore for a period of two years, with about 1 million tonnes produced each year.
The approval of these projects complements the $100 million Tasmanian Jobs and Growth Plan announced by the Prime Minister last month, which supports new, emerging and growing industries.