The gold miner said it was aiming to achieve no net loss in biodiversity and net gains where possible.
IUCN started its review at Newmont's Nevada operations in August and will visit other select mine sites.
"The full assessment of the first site visit to Newmont's operations in Nevada is still being compiled, but preliminary conclusions indicate that there is considerable scope for the mining sector to mainstream biodiversity conservation into their operations in a meaningful way," IUCN global director Stewart Maginnis said.
Newmont executive vice president of sustainability and external relations Elaine Dorward-King said the company hoped to remain a global leader in sustainability.
Newmont was last month named the mining industry leader by the Dow Jones Sustainability World Index for the fourth consecutive year.
The only S&P-listed gold producer's shares were trading above US$40 earlier this year but dropped to $29.16 last month.
They last traded at $30.56, capitalising the company at $16.3 billion.