Officials said about 100 miners were working at the time of the first explosion.

The company currently employs about 700 miners, who have already dug several kilometers of tunnels under the desert.

Around this time the monthly payroll of the mine was reported to have about 400 miners.

The mine, which employed about 450 miners and supervisors before the strike, now has a work force of 125.

These companies employed about 3,000 miners in the district, and Jerome's population rose to an estimated 10,000 by 1917.

In 1980, the department says, there were about 5,600 operating mines and about 215,000 miners.

Last year, the last for which statistics are available, there were fewer than 3,800 mines and about 136,000 miners.

Mine owners say about 225,000 miners are striking at 30 coal and gold mines.

Initially consisting of about 3,300 miners and their families, the district's population have grown over the years to over 18,000.

From 1864 to 1866, the trail was traversed by about 3,500 miners, emigrant settlers and others.