As Chile struggled for two months to rescue 33 miners trapped deep underground last year, it turned to an unlikely tool to help keep them healthy: copper socks.

Chile has built its economy on the world's biggest deposits of copper, a metal known for versatility in a wide range of industrial applications from pipes and plumbing in the home to electrical wiring in power cables to cell phone components.

Copper could soon get another outlet for future demand growth, thanks to the germ-fighting quality that enabled the copper socks to keep the trapped miners free of foot infections in the warm, humid mine.

Copper's anti-infection properties have been known at least since the days of scalpel-wielding ancient Egyptians, but modern medicine has not fully exploited these benefits -- until now.

Clinical evidence to be unveiled Friday is expected to show hospitals can reduce infections by using copper touch-surfaces for everything from intravenous poles to over-the-patient tables, bed rails, door knobs and the nurse's call button. With deadly, drug-resistant bacteria on the rise, researchers have been seeking new ways to fight hospital-acquired infections, the fourth biggest cause of death in the United States behind heart disease, strokes and cancer.

The preliminary results from a four-year study at three U.S. hospitals could be the big break producers like copper giants Codelco and Freeport McMoRan have sought to tap into the multibillion-dollar healthcare business.

We started with an idea and four short years later we now have a potential solution to one of the world's most devastating problems, said Dr. Michael Schmidt, professor of microbiology at the Medical University of South Carolina whose hospital took part in the research.

Schmidt and teams of doctors at the Ralph H. Johnson VA Medical Center in South Carolina and New York City's Memorial Sloan Kettering Cancer Center collected data from copper surfaces to prove that the metal curbs hospital-acquired infections, which kill more than 100,000 people a year in the United States and cost $45 billion per year to treat.

Schmidt, whose research was funded by the US Defense Department and spearheaded by the Copper Development Association, declined to detail the preliminary results ahead of the trial showcase at the World Health Organization in Geneva, Switzerland.

COPPER HOSPITAL

Copper, whose anti-bacterial properties have been given certification from the U.S. government, releases ions that penetrate bacteria and bind to their enzymes and proteins, disabling them. Steel, the material used in most hospitals, does not.

At the Copper Hospital in the mining city of Calama in Chile's far north, head nurse Alicia Gutierrez witnessed a sharp drop in infections after copper plating was installed in some intensive care units.

We've seen how these surfaces have helped cut the number of infections here, she said. I wish everyone could see it and appreciate how it can save lives.

A trial at the hospital, which was built using copper revenues and treats Codelco mine workers, showed copper surfaces killed over 82 percent of bacteria within hours. Other studies show copper killed over 90 percent of bacteria.

Dr. Schmidt said the benefits would be profound for a U.S. healthcare industry struggling with rising costs and falling insurance reimbursement rates.

It's the goal of every hospital to discharge you as quickly as possible ... in order to protect you from hospital-acquired infections and to control costs.

With the passage of the Patient Protection and Affordable Care Act, the U.S. government will begin next year to reward nonrural acute care hospitals that show a reduction in the number of hospital-acquired infections. This could also jump-start the sector.

NOT AN EASY SALE

With super bugs evolving faster than antibiotics, many scientists believe copper could be just what the doctor ordered.

But it still may be an uphill struggle to get hospitals to fill that prescription because of tight budgets, lofty copper prices and uncertainty about just how effective its anti-bacterial properties will be.

The question is whether despite clear health benefits, you are going to be able to persuade governments and hospitals they need to rip out stainless steel or something else they've got in already, said Jon Barnes at metal industry consultants CRU Group.

It's a property for copper that people have tended to forget about. It's a property that should be exploited and does have a part to play, he added

Barnes and many other industry experts doubt the anti-microbial niche could mean big business for miners and manufacturers, as it will take a smaller portion of global demand.

Copper producers estimate between 250,000 to 1 million tons a year in additional copper demand stemming from anti-bacterial uses, or about 5 percent of world's mined copper output.

However, miners and manufacturers are betting anti-bacterial uses for copper can spread beyond hospitals.

It's an exciting opportunity for the industry to have applications in hospitals and clinics, but also in public buildings in general, Richard Adkerson, chief executive of Freeport, told Reuters in March.

State miner Codelco is in talks with health officials in Chile to use copper in new clinics and is already partnered with local companies to manufacture socks with copper fibers as well as copper-plated sea cages for salmon farming.

For Tim Strelitz, president of California Metal-X, a company that plans to manufacture alloys to be used in antimicrobial products, the potential is tremendous.

The future for copper is extremely bright and the benefits that copper is going to end up generating for humanity are very bright.

(Additional reporting by Fabian Cambero in Santiago and Karen Norton in London; Editing by David Gregorio)