CALGARY -- Canmore council delayed its decision on the contentious Three Sisters Village proposal Tuesday, citing the need for further study.

The plan will come back for third and final reading May 25.

In April council voted to reject the developers other parallel proposal, Smith Creek, and then passed a series of amendments to the remaining Three Sisters plan.

The amendments sought guarantees commercial space would be built first, and also doubled the amount of "affordable housing" in the plan from 10 per cent to 20 per cent.

Councillors expressed concern about allowing the development to move ahead without guaranteeing a strong commercial tax base to help support the added residential infrastructure.

According the to company's plans as many as 10,000 people could be added to the town by the time the project completes building in 20 to 30 years.

Developer Three Sisters Mountain Village sent a detailed letter to the town of Canmore last week outlining concerns with the passed amendments. The letter says the changes are major and introduce a number of technical construction and land use problems as well as making the plan unprofitable.

Opponents of the plan say they are also concerned about building over the extensive abandoned coal mining chambers which were designed to eventually collapse, causing slumping of the ground on the surface.

Critics also say the project would further squeeze a narrow wildlife corridor along the Bow Valley's south side. Wildlife monitoring research has shown development along the north side of the valley has largely stopped wildlife such as elk and bears from being able to bypass human settlement in that area.

The developer expects to sit down with town administration between now and the May 25 council meeting to explain their concerns.