TORONTO, July 8 (Reuters) - Shares of Canadian companies

that mine critical minerals such as copper and uranium fell on

the Toronto Stock Exchange (TSX)on Monday as investors assessed

the potential impact of Canada's announcement last week that it

would restrict large mergers and acquisitions in critical

minerals.

Last Thursday, Industry Minister Francois-Philippe Champagne

cleared London-listed Glencore's ( GLCNF ) takeover of the coal

unit of Teck Resources ( TECK ) under strict conditions after taking into

account the "net benefit" of the deal. But he added Canada would

allow large mergers and acquisitions in the sector only under

the 'most exceptional circumstances.'

Six critical mineral companies were among the top losers in

opening trade on the Toronto Stock Exchange. Copper miners,

including Capstone Copper Hudbay Minerals, Teck

Resources ( TECK ), First Quantum Minerals ( FQVLF ), Ivanhoe

Mines ( IVPAF ) were all down by over 3% around 1 p.m. Eastern

Time, while uranium miner Cameco Corp ( CCJ ) was down 2.13%.

"This updated policy significantly compresses M&A

optionality and potentially restricts financing options for

Canadian miners. As a result, we now anticipate most Canadian

miners to trade at lower valuation multiples vs. global peers,"

said an analyst note led by Scotiabank analyst Orest Wowkodaw.

Champagne said the ministry would set a high bar for

clearing future deals involving large Canadian companies in the

critical minerals sector, reflecting the strategic importance of

critical minerals and the need for Canada to protect its

interests.

Canada has identified 31 minerals, including copper,

uranium, lithium and nickel, that it considers critical for

their strategic uses in modern technology and the transition

from fossil fuels, such as in electric vehicle batteries.

"The door has not been closed, but narrowed even further on

investments in critical minerals...," said Calvin Goldman,

former head of Canada's Competition Bureau, who now runs an

independent practice on advising clients in foreign investments.

"So business community, get ready because you have to be fully

prepared, as now they have to satisfy increasingly quiet strict

criteria," Goldman added.

Under the Investment Canada Act the government can reject a

proposed acquisition or any inbound foreign investment if the

government believes the deal represents a threat to national

security or if it fails to satisfy the criteria for bringing a

"net benefit" to Canadians.

In the last two years, Canada has asked Chinese investors to

divest from Canadian critical mining companies after a national

security review, signaling that investments from certain

countries such as China will come under tougher scrutiny.

Some of the largest investors in leading Canadian copper

companies are Chinese. Teck Resources ( TECK ) counts China Investment

Corp as its biggest shareholder. First Quantum's largest

shareholder is China's state-owned copper miner Jianxi Copper

and Ivanhoe Mines ( IVPAF ) has Hong Kong-headquartered CITC

Metal Group has its leading shareholder.