A bull market in metals has helped fuel a surging demand for commodities used in everything from power plants to car engines.
Metal prices have surged as the global economy has bounced back from the global financial crisis.
But the rise has coincided with a slump in the price of commodities used for power plants, which have become more expensive in recent years.
As the price for these commodities has risen, so too has demand for metal mining, a commodity that has become increasingly important in recent decades.
A boom in the metals market has helped to keep prices steady for several years, and the boom has helped keep the price steady, according to Andrew R. Smith, the chief executive of Smith Gold Mining, which operates a copper and nickel mining operation in Texas.
A surge in demand for metals, combined with a glut in metal ore, has also helped keep prices high for many years, Smith said.
The metal markets have been growing for years as demand for goods like steel and aluminum has skyrocketed, Smith added.
The boom in demand has helped boost the value of metals in the economy.
But now metal prices are starting to come back to earth, said Mark D. Anderson, an analyst at Morningstar.
Demand for metals has slumped since the global economic downturn began in 2008, he said.
And as demand picks up, prices are expected to pick up again.
In December, metal futures prices in the U.S. averaged $1,265.55 a ton, up 1.7 percent from the previous month.
Gold, by contrast, had fallen about 9 percent in the past year and 5.7% from a year earlier, according the Bloomberg Commodities Index.
Metal mining, like the rest of the commodities market, has been volatile in recent weeks.
On Wednesday, prices for copper dropped nearly 2 percent to $1.941 a ton from $1-1.98, according in the London-based metal broker Metal Index.
On Friday, prices were flat to down more than 2 percent for nickel at $1 per pound from $2.50 per pound, according data compiled by Bloomberg.
The futures market for gold is down 6 percent from a record high of $1 million in September.
The commodities market for the metals sector has been on a strong run in recent months, but the bull run is starting to fade, Anderson said.
Gold futures fell 6 percent on Thursday to $2,061.85 a ton in London, the lowest since June.
On Thursday, gold futures prices averaged $3,715.86 a ton.
Copper was up 4.5 percent at $3.742 a ton and nickel was up 2.4 percent at the lowest level since July 2009.
Silver fell 1.4% to $4,619.23.
Gold fell 0.8 percent to its lowest level in three years.
The prices of gold, copper and silver were all lower Thursday compared to a week earlier, compared to the highs of the past two months.
The silver and copper markets have seen their own bull runs this year, and prices for metals are also at their lowest levels since early last year.
Gold and copper prices have been at record highs, but they have started to decline since the summer of 2014, when the market for those commodities was on a roll, Smith noted.