Toronto's claim as the world's top mining hub is under threat as exploration companies leave Canada and listings dwindle on the nation's resource-heavy stock exchange, Bloomberg News is reporting Monday.

Bloomberg said Canada's once-thriving mining industry is facing challenges to its decades-old model, in which explorers and developers woo investors with promises of mining breakthroughs and established producers feed on their success, swallowing them in lucrative takeovers. Industry consolidation has reduced head offices and eliminated listings, companies find it harder to attract investors, and government rules on foreign investment have become more restrictive, it added.

"The industry that has fueled most of the great Canadian minerals discoveries over the past 50 years is but a skeleton of itself," said mining financier Pierre Lassonde, who co-founded Franco-Nevada Corp. "We should be extremely concerned."

Three small firms shut their Canadian headquarters in the past nine months to relocate to other countries: Lithium Argentina AG, Solaris Resources Inc. and Falcon Energy Materials Plc. At least two others -- Cornish Metals Inc. (CUSN.V) and Almonty Industries Inc. (AII.TO) -- are embarking on similar plans. It's not just small companies: Toronto-based Barrick Gold Corp. (ABX.TO), the world's No. 2 miner, has mused about redomiciling to the US.

As executives, bankers and investors gather this week for the annual Prospectors and Developers Association of Canada conference in Toronto, the health of the industry is top of mind for attendees visiting this global mining epicenter, Bloomberg noted.

The Toronto Stock Exchange and the TSX Venture Exchange represent 40% of the world's public mining companies, providing home to 1,097 listings, exchange owner TMX Group Ltd. said in its latest listings guide. That's down from 2010, when the exchanges had 1,531 mining companies to account for 56% of global listings for the industry. The decline comes as stock markets in London, Sydney and New York have been competing to attract mining companies.

Bloomberg noted Allied Gold Corp. (AAUC.TO) is applying for a listing on the New York Stock Exchange, joining an industrywide migration to the world's top bourse. The Toronto-based company would join a long list of gold miners that are on both Canadian and US exchanges.

New York's status as a global hub for gold equities expanded in recent years after a series of major deals transformed the industry and created two North American titans -- Newmont Corp. and Barrick -- that trade in the US city. Barrick has long been headquartered in Toronto, though last month the Globe and Mail reported that CEO Mark Bristow said he was considering redomiciling to the US. Barrick didn't respond to requests for comment.

Toronto's dwindling mining listings over the past decade can be partly chalked up to consolidation and shifting focus, according to TMX Group. About half of mining delistings were tied to mergers and acquisitions, and 27% were companies that converted to cannabis firms.

A dearth of initial public offerings in recent years hasn't helped stem the decline. There were no significant mining IPOs in the past year. Back in 2010, 90 miners went public after collectively raising $1.26 billion.

(Market Chatter news is derived from conversations with market professionals globally, and/or from other media sources. This information is believed to be from reliable sources but may include rumor and speculation. Accuracy is not guaranteed.)