Book Description

This paper is one of series being prepared by the United States Bureau of Mines on mining methods, practices, and costs in the various mining districts of the United States. It describes the mine of the Hanover Bessemer Iron & Copper Co. at Fierro, Grant County, N.M., which is the only operating iron mine in the southwestern part of the United States. This mine is in a district noted for the great variety of ores that it produces. Within a small area, as shown is Figure 1, there are noteworthy deposits of nearly all the common metals. The ore occurs in lenticular masses dipping at about 50°. An underhand stoping method has been developed that requires but a very small amount of handling of ore. As the ore is very irregular in iron content and also in the distribution of the impurities--chiefly sulphur, silica, and magnesia--a method has to be used that will permit selective mining and will also allow ore and waste to be taken out separately as conditions change. A magnetic cobbing plant raises the grade of the ore shipped about 10 per cent. Nealy all of the iron ore is shipped to Pueble, Colo., a distance of 694 miles, where it is smelted by the Colorado Fuel & Iron Co. The mine is not a large producer, as the long distance from blast furnaces limits its output. In recent years the annual shipments have amounted to about 200,000 tons. The property is noteworthy chiefly on account of this long transportation by rail and the economical methods that have been developed to make the operation profitable. About 175 men are employed.