By Luis Andres Henao

BUENOS AIRES (Reuters) - Argentina's Senate passed
a law Thursday that curbs mining on and around the nation's
glaciers to protect water supplies, a measure praised by
environmentalists but criticized by industry supporters.

Analysts and an Argentine mining chamber have warned that
the law could hinder construction of the massive Pascua Lama
mine, which is being built high in the Andes by the world's
biggest gold miner, Barrick Gold Corp.

Senators approved the law 35 to 33, agreeing to include
changes made in the lower house that pro-mining provinces had
opposed. Some analysts say provincial government could seek to
overturn the law in the Supreme court.

"This vote cut across all party lines and I think we passed
the best proposal," ruling party lawmaker Miguel Pichetto told
local radio, adding that he expected President Cristina
Fernandez to sign the bill into law promptly.

Fernandez has indicated she will sign the law this time
around after vetoing a similar measure two years ago on the
grounds it would hamper growth of provincial economies, a
decision that angered environmental groups.

The new law, which also bans oil drilling on the country's
glaciers and the surrounding areas, aims to safeguard water
reserves. It sets standards for protecting glaciers and
so-called periglacial areas and penalizes companies that
pollute or damage ice fields.

"Water is a human right, gold is not," Sen. Daniel Filmus,
one of the bill's backers, told Reuters in a recent interview.
"If any of these mining projects includes work on glaciers or
surrounding areas, it will be banned outright."

BARRICK MINE

Analysts say it could make it more expensive or even
impossible for Barrick to develop the Pascua Lama site,
although the company says the ore body it has permission to
mine does not lie under a glacier.

"We do not mine on glaciers, and in fact, Barrick has
already implemented a comprehensive range of measures to
protect them as well as other sensitive environmental areas
around both the Veladero mine and the Pascua Lama project,"
company spokesman Rodrigo Jimenez said in a statement.

"We will continue with our normal activities and comply
with the applicable legal framework," he added.

Gold mining companies were trading lower in Toronto, but
Barrick might have taken an extra hit due to the passing of the
glacier law.

Haywood Securities analyst Kerry Smith said the news might
be having a "marginal" effect on Barrick's shares, which were
trading down more than 2.7 percent at C$47.25, but added that
the lower gold spot price was more likely driving shares down.

Barrick says it has already committed more than 25 percent
of the capital for Pascua Lama, with the project's
pre-production capital budget estimated at $2.8 billion to $3.0
billion.

Pascua Lama straddles the Argentine-Chilean border and is
located in Argentina's San Juan province. Barrick's Veladero
mine, also in San Juan, produced 611,000 ounces of gold in
2009.

Mining-friendly provincial governments such as San Juan
might try to challenge the law in the Supreme Court, arguing
they have the right to decide how to manage their natural
resources.

Constitutional experts say the law could trigger a lengthy
legal battle that could disrupt or end Barrick's plans. They
say the company also could eventually seek compensation.

Anti-mining sentiment is strong in the South American
country, making the debate over the glacier law a sensitive
political issue a year from the next presidential election.
(Additional reporting by Jorge Otaola and Helen Popper in
Buenos Aires and Cameron French and Julie Gordon in Toronto;
editing by Jim Marshall)