48 KANSAS CITY REVIEW OF SCIENCE. 



This battery is a knee battery of forty stamps, makes ninety-five drops per 

 minute, and is capable of crushing 124 tons every twenty-four hours. 



From the battery the sand, as it has now become, is run into settUng sand 

 tanks, there settled, and shuffled into pans for amalgamating. 



These pans, often erroneously called tubs, are placed in rows, in what is 

 known as the pan room. There were in this instance twenty combination amal- 

 gamating pans employed, of two tons capacity to the change ; and with ten set- 

 tlers capacity for the pans. From the settler bowls quicksilver is taken in 

 pipes to the strainers ; from the strainer safes, again in pipes to the reservoir of 

 the quicksilver elevators, and to the pan floor into another receiver. From this 

 it is taken in pipes to the bowls on the pans. Down from these bowls the quick- 

 silver is let by charges into the pans, as needed to charge them — these contain 

 the ore now reduced to a fine mass — for amalgamating 



The ore, now called amalgam, is ready for retorting. After retorting the 

 crude bullion is hauled on to an iron plate, broken up, put into crucibles, and 

 smelted into bars, generally a foot and a half long, and eight inches thick. All 

 that remains is to ship it to the mints. 



In the mill visited the engine was 24 by 48 inches, of 250 horse power, the main 

 belt thirty-six inches in width, while the main driving pulley of the fly-wheel had 

 a capacity of 39,000 pounds. The boilers, four in number, were fifty-six inches 

 by sixteen feet in diameter, of 250 horse power capacity. This is what termed 

 the " wet " process, as the roasting does not do for poor grade ores. In the mill 

 described, ores have been worked for less than $5 per ton. 



Were I a practical miner, I would be able to enlarge upon these details, and 

 give them with more force and clearness than I have done. As I am not, I may 

 only submit them as the skeleton of a description, trusting that those who read 

 it, may gain from it a slight idea of a model low-grade stamp mill. 



MINING PROSPECTS IN COLORADO FOR 1882. 



From an average production of only three or four millions, Colorado has 

 suddenly risen to the first rank as a producer of the precious metals among the 

 States and Territories for gold and silver combined ; as for silver alone, it ranks 

 first, while for gold it holds the fourth rank. In the relation of production to 

 area, it holds the first rank, likewise, for gold and silver combined and for silver 

 alone, and the third for gold alone. In the relation of production to population, 

 however, it ranks only third for gold and silver together, second for silver alone, 

 and sixth for gold alone. The total value of its product during the census year 

 in gold and silver was, in round numbers, nineteen and a quarter million dollars, 

 and if we add to this the value of lead and copper in crude metal produced, we 

 have a total value of metallic product of twenty-two and three quarters million 

 dollars. 



