Explorer Minerals 260 says its Bullabulling project in WA’s Goldfields region will yield for almost two decades and is Australia’s biggest undeveloped gold reserve not owned by existing producer.

The Luke McFadyen-led company has released an updated, 38 per cent larger mineral resource estimate for the project, situated 25km west of Coolgardie.

Its pre-feasibility study also landed on Wednesday, outlining a plan to produce 150,000 ounces per annum for 19 years, starting from the December quarter of 2028.

Minerals 260 - which has had a staggering share price surge over the past year, giving it a market value of almost $1.8 billion - said the operation would have an all-in sustaining cost of $A2520/oz ($US1747/oz).

Bloomberg reports spot gold was trading at $US4098.04/oz ($A5909/oz) just before 7am in Singapore.

“Bullabulling is firmly established as one of Australia’s premier gold development projects and our strategic objective of creating a large-scale operation by the end of 2028 continues to progress rapidly,” Mr McFadyen said.