Arizona silver belt., 1899-10-19
CONCENrR ATES.
Items of Interest in Regard to Mines
 and Timing.
From Mining and Scientific Pres,

emery in all the uses of that abrasive. and is produced in large quantities at Niagara Falls, N. Y.
 The De Beers diamond mine, in South Africa, is considered to be the largest mining dividend payer in the world; it paid last year oI,6S7o90.
 Superheated steam is that which is further raised by the application of additional heat toa temperature above that which belongs to it's equilibrium of temperature and pressure when in contact with itS.liquid.
 Machine drills do not work to ad- vantage in soft ground. The bits cut rapidly but quickly churn the soft material into a thick paste that is pounded into the bottom of the hole, retardiug the operation of the drill.
 Blankets were at one time much in use for the purpose of concentrating sulphides from tailingS hut they have in recent wears been replaced by cheap brussels carpet orStillmore commonly by canvas of various grades.
 When required assessment work on unpatented mining claim has been actnally done. and can be definitely proved by responsible witnesses, no one can legally jump" that claim. It is. however, safer to record the work,
 Sea water is successfully employed in extracting gold by means of the cyanide process, in Chile. The line gold found in some beach sands could probably be extracted in the same manner. II is a material well suited tO teaching.
 In some of the Central American countries the native miners strike single handed. using a l0-pound ham mer having handle Is inches in length. The blows fall slowly. but in time they put hole down. Thcycun- slider a 3l-pound hammer q toy.
 Magnetic k magnetic iron ore. usually occurring in octahcdran>. also in dodecahedronS, often granular; sometimes found in detritic form be tween sheets of mica. forming peculiar and interesting figures. but destroy ing the mica for commercial Uses,
 Wolframite is the technical term for ungstatc of iron. Ilumcrite iS the term fer tungStaje of maugdueSe. both of which are found in the vicin- ity of Gladstone. Colo. Stolgitc. tung- state of lead k believed to exist in the Red mountain. Colorado ores.
 In many of the gold-heaing veins of southern California. Arizona and southern Nevada molybdatc of lead occurs in small quantity and is often mistaken for gold by inexperienced propectors. when banning the crushed ore ItwilI becomplctely d"rWmposed by hydrochlorr acid
 American mining machinery k se- curing worldwide recognition on Ils merits. In south America. south Africa. Australia Russia. Japan. etc. fhc most advanced mine managers, regardless of nationahty. >tipulate that mining machinery of American manufacture shall bc used.
 \ vendor who brings principals 10 gcthcr is in general considered to he entitled io commissions whether busi- ness iS done direct. or through him. such matters arr. however determ- ined largely by special agreement, which. in q ease Of any consequence, should he in writing. Su wordcd that the intent cannot bc misunderstood
 Propolite is rock which has been re- cognized as q distinct species by sew eral writers of note. among them Iir- kel and Stache Later microscopic investigation has resulted in the gen cral opinion that prGpylitc is altered hOrnblcnde andeSite. in which the hornblende material has penetrated the feldspars during the process of al- teration. and the hornbcndc crystals are found altered to chlorilc and cpi- dOte These rocks contain quartz and are found without it.
 Conglumcrtc is mass of gravel, sand and cohblcS. all more or less rounded by atlrition on q lake or sea shore or in river bed and cemcnted by some material such as lime. iron oxide. silica. etc. Brcccia is q mass uf material similarly concealed. bul the fragments are all angular. may be the result of q volcanic eruption or may be rock iIi situ which has been fractured hy dynamic forces and sub Scqucntly ccmentcd. Either may con tain ores and valuable metals.
 ELThc drying of ores by calcining pre- yiouS t0 dry crushing often does more harm than good. particularly where inc ores contain much sulphide min eral. as the partial oxidation of the