The cost of the Trans Mountain Expansion pipeline project is now an estimated $30.9 billion, Trans Mountain Corporation said Friday.

The company said inflation, supply chain issues, flooding in British Columbia and unexpected archaeological discoveries were among the main factors behind the cost increase.

It also pointed to challenges around terrain, water disposal costs and dense population in areas between Sumas and Burnaby, B.C., and labour shortages.

The expansion project aims to triple the pipeline’s capacity to carry 890,000 barrels of oil per day from Alberta to British Columbia.

The 980-kilometre pipeline expansion is “close to 80 per cent complete,” the company said, and it’s pushed expected in-service date back to the first quarter of 2024.

Costs for the pipeline development were pegged at $21.4 billion as of last year, still significantly higher than the previous $12.6 billion estimate.

The federal government has said it plans to halt funding for the taxpayer-owned project and intends to eventually sell it to the private sector, but the Parliamentary Budget Officer has already warned that the government could lose money on the sale.