Arizona republican., 1898-07-01
CYANIDE PLANT AT MERCUR.

What is probably the most remark able cyanide plant in the world has just been put in operation on the Col den Gate mine at Mercur, Utah, the property of Captain De La Mar The ores of the Mercur district were for many years puzzle to scientists, but after long series of experiments 1t was found that they could be success fully treated by cyanide, and the re- suit was the erection of this big plant at cost of $1,500,OO0, description of which will be of interest to mining men and mill men all over the coun- try.
 The site covers an area of 300x400 feet. In the foundation is cement7d 5000 tons of masonry, terTaced till were it run perpendicularly the height would be 300 feet above the earth. The mill building, of steel, is 160 feet from the lowest to the highest floor level and is 3S0 feet long by 295 feet wide. On the top or upper level is Gates crusher, 25x75 feet. The ore is raised through an incline which starts from the working shaft about 60 feet below the surface, and passing up under corner is automatically dumped into the coarse crushers and run into bins holding 1000 tons. The dryer on the second level rests upon solid masonry 40 feet thick with floor space 75xS2 feet From this the ore passes to the third level, where are placed the rolls, screen nd elevators, and where it is finely t.ushed and screened, thence go- ing to 25x84 foot of ore bins each of 2,000 tons capacity. Under these ore bins is dust chamber 11x100 feet, di- rectly connected with the main Hue and provided with eight hoppers.
 From this second set of bins the sul- phides and arsenical ores discharge in to two Brown drying furnaces, rever- beratory, hearths 12x6O feet, fired by gas, on the fourth and fifth levels. The silicious ores go directly from the stor- age bins without roasting. The sixth level is reserved for additional flcor space. On the seventh level, with a floor 298x60 feet, are ten solution tanks each having 200 tons capacity, into which the ore is discharged from a tunnel running from the fifth and sixth levels. On the eighth level are the precipitation tanks charged with zinc shavings.
 South of the fourth level is gas making plant 30x6S feet The gas is used for roasting and drying and, it is claimed, effects saving Of 25 per cent in the fuel bill Eleven dXnamos of a combined capacity of 600 horse pow CT furnish the power.
 The ores of Mercur are mainly low grade carrying about s5 in gold to the ton The first discoveries were of sil- ver-high grade chlorides. This was soon worked out, and a vein of Cinna bar found. Finally the great deposits of gold ore were uncovered. An enor- nous quantity of $5 ore has been blocked out during the past three years. In the mine the cave-in system has been adopted. The drifts are -un under the ore body next the foot wall and timbered just enough for safety. The ore is then divided into blocks, every block being left standing remain ing as support to the hanging wall. The remaining blocks are then mined out and the pillars are broken down by running a drift along the hanging wall and loosening the pillars, allow ing the loosened ore to pass by gravi- tation to the openings.-Denver Re- publican.