MONTREAL -- A landmark tract of land at the edge of Old Montreal will undergo a transformation after Molson Coors announced plans to spend up to $500 million to build a new brewery instead of modernizing North America's oldest brewery along the St. Lawrence River.

The brewer's decision, which follows a two-year study, was announced to employees on Wednesday.

Molson Coors Canada CEO Fred Landtmeters said the company is exploring options to ensure Molson's heritage is commemorated at its original location which opened in 1786.

"The Montreal brewery is an emblem and this historic site will be an invaluable legacy for the city," Landtmeters said in a news release.

The brewer (TSX:TPX.B) has said it plans to maintain a microbrewery and store at the 231-year-old site near Old Montreal, with the rest being sold for redevelopment under the auspices of the city.

Landtmeters said building the new brewery will be more efficient than updating the existing operations.

The location of the new operation hasn't yet been determined, but it is expected to remain in the Greater Montreal area. The next step will be to develop a business plan for the construction of a new Quebec brewery in about five years.

Company spokesman Francois Lefebvre said it's too soon to know if there will be any impact on the 1,000 employees who work at the brewery and a nearby distribution centre.

The new location will include production and distribution at the same site.

Local union president Eric Picotte of the Teamsters welcomed the decision to maintain a long-term brewing presence in Montreal.

However, he said the company hasn't said if it will maintain production of bottles and cans or switch to cans which require substantially fewer employees.

"There are no guarantees and that's what worries us," he said in an interview.

Over the last six years, Molson Coors has shifted more production to cans, which has resulted in the loss of more than 100 employees, Picotte added.

Molson Coors sold its operations in Vancouver last year. The company will continue to produce beer at that site for up to five years while it builds a new facility in Chilliwack, B.C.