The economics of coal revolved around two factors: most of the cost of production was wages for miners, and if the supply fell, the price would shoot up. In an age before the use of oil and electricity, there were no good substitutes. Profits were low in 1902 because of an over supply; therefore the owners welcomed a moderately long strike. They had huge stockpiles which increased daily in value. It was illegal for the owners to conspire to shut down production, but not so if the miners went on strike. The owners welcomed the strike, but they adamantly refused to recognize the union, because they feared the union would control the coal industry by manipulating strikes.