"This is a classic dilemma between economic development and environmental conservation. These are never easy questions," Chris Carter, New Zealand's conservation minister, told Reuters on Wednesday.

Many countries facing similar challenges are meeting at the 8th United Nations conference on the Convention on Biodiversity in Brazil this week to discuss ways of slowing the pace of biodiversity loss by 2010.

Right now, extinctions are more widespread than at any time since the age of dinosaurs, experts say.

The snail, Powelliphanta Augustus, is just a couple of inches (centimeters) long, including its shell. But its isolated population has forced state-owned company Solid Energy to offer plans to save the snail. The company is eager to mine an estimated $300 million to $540 million in high-grade coal that lies beneath the surface.

The energy company has suggested lifting topsoil from the carnivorous snail's 5-hectare (12-acre) habitat of shrubs and moving it away from the lunar landscape of mines surrounding it.

The company might also build a fence to protect the snails from predators in the new area and start an incubation project to breed them. Carter has yet to decide on this plan, though he did allow the company to relocate a different, smaller group of snails on Feb. 27.

Environmental groups in New Zealand say Happy Valley is home to several threatened species which would be obliterated by mining.

Carter said he will not sign off on the company's plan, which he called a "generous offer," until scientists conclude whether the snail population would survive the move or if it should be left untouched in its habitat above the coal.

"The question is if this mitigation will be enough to save the species," he said.