Emerald Isle Mine - Mohave County
Where: Located in the Cerbat Mountains near Chloride
Travel Conditions: Well traveled dirt road with side rode to mine. There is a locked cable blocking the entrance to the mine.
Operation Dates: Operated 1943 to 1948. Early workings were started in 1917 in this area.
Description: An unusual type of copper deposit is found at the Emerald Isle mine, located about a mile west of Mineral Park, Wash. The mine was idle when visited early in 1943 and again in 1950. It was worked at various times from 1917 to 1943, and late in 1943 the Emerald Isle Copper Co. resumed mining and began the erection of a 300- ton leaching plant, which was completed in 1944. Mining continued until June 1946. In 1947 the Lewin-Mathes Co. Started operations on the property and continued work until June 1948. About 55,000 tons of copper was recovered from the ores during the period 1943-48.
Mining in the early days was carried on chiefly from underground workings, although work since 1943 has been done almost entirely from an open pit. The underground workings were inaccessible when
visited. Two short shafts were sunk, and according to reports the main shaft is 90 feet deep, penetrating 80 feet of gravels and boulders and, at the bottom, 10 feet of bedrock. In the gravels near the bottom of the shaft a drift extends northeastward for about 300 feet, and another drift extends southwestward for about 1,100 feet. Until 1943 most of the surface work had been done in a small pit about 400 feet east of the main shaft. When visited in 1950, the open-cut work had been extended westward to the upper part of the old underground workings northeast of the main shaft.
The deposit consists of a fissure vein and an irregular area of mineralized alluvium bordering the vein chiefly on the east. The mineralization consists of bluish-green chrysocolla and shiny black copper pitch (probably an impure copper silicate).
The large open pit, which to date has yielded most of the copper ore, furnishes good exposures of the chrysocolla-bearing alluvium and also the upper part of the fissure vein. The mineralized alluvium consists of copper pitch and chrysocolla coating particles and filling interstices in the various-sized outwash material of the valley. Except for a few mineralized fissures, striking northeast, and the vein near the "shaft, the walls of the open pit show the individual copper-bearing bodies as concentrations of the chrysocolla and copper-pitch cement in irregular lenses and pods ranging from a few inches to several feet across. The outlines of a few of the lenses are clearly controlled by the bedding of the debris. Boundaries of the mineralized parts are commonly sharp. In places the finer-grained gravels and grits are uniformly dull green, which may in part be due to material other than copper. The richer parts are the typical bluish green of chrysocolla.
The gangue consists of alluvial material ranging from sand and grit to boulders as much as 4 feet long. The debris is commonly subangular to angular and composed of rocks from the pre-Cambrian crystalline complex as well as from the Mesozoic (?) granite. Granites of various types predominate to a great extent, although a minor amount of volcanic material is present. The material in the pit is fairly well cemented. (http://pubs.usgs.gov)
What you will see today: There is still and old building as seen in the photos with two large tanks present. There is a business type trailer parked inside the gate that is a more recent addition. The old open pit mine pit looks as though it has not been worked in many years with signs of brush and crevises where water has ran down the sides. There is some evidence of recent activity with some piping and a pump present near small pond. Some old concrete structures/footings are close to the open pit area from old activites. Visited in July of 2015.
Comments: Easy place to get to and view. There is a sign near the entrance road with the name SGV Resources, Inc. with an address and local phone number. The trailer on the property is more recent but there are no signs of major work going on at the facility for awhile.
Minerals Mined: Major mineral mined here was copper with minor amounts of gold and silver present.
Acknowledgement: http://pubs.usgs.gov and www.mindat.org