Halfway up a stone-strewn hillside, Rob Wetzel picks up a fist-sized rock glittering in the morning sun.

“Quartz monzonite,” he says. “Those sparkles are copper minerals.”

Towering 200 feet above Wetzel are the remains of the Engels Mine processing plant, which produced 161 million pounds of copper from 1915 until 1930. Below him, Lights Creek cascades out of the northern Sierra Nevada toward Indian Creek and the Feather River.

Wetzel, a geologist, and his company, Sheffield Resources Ltd. of Vancouver, British Columbia, are exploring this remote corner of Plumas County to study its copper fields. They hope to reopen Engels Mine and dig up new copper deposits on national forestland, in Moonlight Valley.

That has local residents alarmed over potential impact of an operation that could include a 100-acre open pit mine. Concerns range from increased traffic and noise to air and water pollution.

John Shower, an avid angler who lives four miles from Engels Mine, is particularly worried about the effect of an upstream mining operation on Lights Creeks, which flows past his house.

“We moved out here to the end of the world, and I end up right below drilling with trucks and maybe poor water quality. It’s scary,” he said.

Sheffield has spent 18 months studying the quality and quantity of copper deposits in a mineral belt that extends through northern Plumas County into neighboring Lassen County near Westwood, said Wetzel, the company’s Moonlight project manager.

“We hit better mineral grades and thicknesses than we expected,” he said of the exploration, so far.

By late 2008, the company should know whether the copper bed will support a full-scale commercial operation.

Part of the Moonlight project involves the tunnels dug by Engels Mine Co. early last century. Two separate copper mines flourished here for more than a decade, employing as many as 600 people working around the clock. The operation in the north arm of Indian Valley supported a lively community of around 2,000 residents.

The mines were closed in 1930 when the price of copper plummeted to 5 cents a pound, said Norm Lamb, president of the California-Engels Mining Co., which now owns the 1,000-acre property.

Today a pound of copper fetches $3.40, an increase driven largely by increased demand from China. That is propelling Sheffield’s exploration of the Plumas County deposits, Wetzel said.

If company officials conclude that commercial mining is economically feasible, they will begin applying for state and federal permits, he said. They have a lease-purchase agreement with Lamb for the Engels Mine land, which is privately owned.

The Moonlight project could create up to 100 jobs over 25 years, around 50 of them permanent. Most of the workers would be hired locally, Wetzel said.

A copper mine could be a boon to the area with an average unemployment rate of around 10 percent. Many local business owners are enthusiastic about the prospect of a new industry in the valley, where jobs lost when lumber mills closed in the last decade have not been replaced.

“From a business standpoint, I’m in full support of any new jobs since we have no industry at all right now,” said Don Williamson, a manager at Evergreen Market in Greenville.

But neighbors of proposed mines are less concerned with jobs than quality of life in their remote valley. Shower, a retired teacher and Santa Cruz real estate broker, lives well within earshot of the daily blasting expected to take place over the 25-year life of Sheffield’s operation. Dust from the drilling and acid drainage from the mines pose health risks to his neighborhood as well as residents in nearby Taylorsville and the rest of Indian Valley, he said.

A commercial mining operation could also lower property values, Shower said. “If this mine comes to pass, I’ll have to sell,” he said.

Sheffield officials, who predicted no more than three trucks a day during full operations, are aware of the potential impacts on local residents. Preliminary tests of mine water show no signs of acid leaching into streams or the water table from past operations, Wetzel said.

Casting a shadow over the proposed operation is the memory of Calgom’s Goldstripe open pit mine 20 miles west of the proposed Moonlight project.

When the mine closed in 1992, the company left a litter of diesel drums and wrecked machinery, 7 acres of cyanide-soaked ore and a yawning pit with dust devils twisting where ponderosa pines and firs once towered. Forest Service officials said the Canadian-based company had complied with all cleanup regulations under the Mining Law of 1872.

That kind of environmental devastation could not happen under current regulations on federal land, Wetzel said. Moreover, the government requires bonds of at least $10 million — enough to cover the cost of reclaiming the land.

The only proposal Sheffield has made involving national forestland is for the current exploration. An application for a full-scale commercial mine would require extensive studies and numerous public hearings, said Erika Sharp, an assistant resource officer with the Plumas National Forest.

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