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Show SIMPLE ORE TESTS FOB PROSPECTORS Impressive methods by Which Presence of Minerals May Be Determined. MAY SAVE UNNECESSARY EXPENSE OF ASSAYING An Elaborate Chemical Laboratory Labora-tory Not Necessary for Many Valuable Tests. Judging by the number of worthless samples submitted to aasnyera to be tosted for various motalH, and by the fact that valueless minerals are often supposed to be valuable ores. It Is evident that many do not realize how easily some elements may bo detected. Naturally a prospector cannot br- expeclod to burden bur-den himself with the equipment of a chemical laboratory, but an outfit, consisting con-sisting chleflv of n few chemicals, blowpipe blow-pipe and spirit lamp, adds llltle bulk of weight and may bo of Inestimable service. The purer the substance to be tested the better, and, should the mineral be scattered through the rock In fine particles, par-ticles, It is usually well to first concentrate concen-trate it by pulverizing the .sample and then panning In water, the concentrates being subsequently dried and. If necessary, neces-sary, ground finer. A clean six-Inch fry. Ing pan Is very convenient, both for washing wash-ing and drying what is left. Cold ores, when crushed and panned, generally show either free metallic gold or sulphides, or other concentrates containing con-taining gold, which, however. Is not visible. If .these sulphides be roasted over a fire ai a dull red heat, on thin Hheel-Iron. say a piece of tin can, and thfn re-ground In a mortar to polish the gold, tho metal In many cases will be plainly seen on panning again. Should the material be oxidized, and when powdered pow-dered and panned show nothing bul the magnetic oxide of Iron, commonly called "black sand," the sample Is apt to be worthless or very low grade, for the writer's experience leads him to bcllevo that, as a general tiling, the black sand Itself obtained from rock in place carries little or no gold, The dried black sund can be readily picked up with a magnet. Greenish rocks are somcMmcs mistaken mis-taken for ores of copper, which metal may, however, be easily detected In the following manner: Pour Into a tos) tube say half an Inch In diameter, enough of the finely ground material to cover the bottom to a depth of about half an Inch, add two or three times as much strong nitric acid, and boll gently over an alcohol alco-hol lamp until the acid seems to have no more effect and red fumes have ceased to come off. Dilute the solution with one or two volumes of water and hold a clean, brlcht piece of Iron or steel, such as the blade of a pocket knife. In tho liquid for a few moments, when, if present, pres-ent, a thin film of metallic copper will bo plainly seen on the blade upon withdrawing with-drawing anil dipping it In clean water. Instead of testing this solution with Iron or steel, strong ammonia may be added In excess lo Ihe liquid when cool, that is, the test tube, after being well shaken, should smell of ammonia. The addition of the ammonia generally produces pro-duces a reddish-brown precipitate due to iron, and the lube should be set aside for a few minutes until this settles somewhat. some-what. If a copper mineral, the liquid will hax'e a deep blue color, the more copper the deeper the color. Nickel solutions so-lutions similarly treated become blue, which, however, is fainter than the color produced by copper, and In nnv event the ores of nickel are apparently not widely distributed. There are many nther tesls for copper, but the two described require little time, knowledge or skill, and are as cood as any for practical pur-poses.- Gordon Surr In Mining World. |