Nickel exchange traded funds strengthened Friday after the Philippines, one of the largest nickel-producing countries, ordered a review of existing mines and their impact on the environment and people.

On Friday, the iPath Bloomberg Nickel Subindex Total Return ETN (NYSEArca: JJN) surged 6.3% and iPath Pure Beta Nickel ETN (NYSEArca: NINI) jumped 4.6%.

Nickel prices rose $0.2616 to $4.5021 per pound.

“People are getting excited about the Philippines,” analyst David Wilson at Citi, told the DailyMail.

Regina Lopez, a staunch environmentalist and the new head of the Department of Environment and Natural Resources, said the government will be reviewing all existing mining operations in the Southeastern Asian country.

“Responsible mining means people must not suffer. Any mining operations should not cause suffering,” Lopez said. “I do want to evaluate if the country is safe from mining.”

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Ramon Adviento, senior V.P. at Global Ferronickel Holdings Inc, the country’s second-biggest nickel ore miner, said the industry was “shell shocked” by Lopez’ appointment, Reuters reported.

Philippine miners warned that hardline policies could backfire, especially as the Philippines has become the largest nickel exporter to China after previous top exporter Indonesia banned shipments of unprocessed minerals.

Moreover, nickel prices were also being supported by a weakening U.S. dollar, which has been lower three of the past four sessions. The USD has depreciated as markets anticipate an extended low-rate environment in response to the post-Brexit uncertainty.

Related: Strong U.S. Dollar, Global Uncertainty Weigh on Oil ETFs

“We had Brexit and there is market expectations of interest rates to remain low,” Alan Liew at United Overseas Bank, told the DailyMail. “It is good for commodities.”

For more information on the nickel market, visit our nickel category.

iPath Bloomberg Nickel Subindex Total Return ETN