Show the pinder concentrator the joshua hendy machine works of san francisco Cali california forDia is sending out a finely illustrated catalogue descriptive of the pinder concentrator the mechanism and operation of which is described in this interesting work as follows we have spared neither time nor money in our endeavor to improve in all possible ways the construction of this machine it being our desire to give our customers not 0 only 1 as good a concentrator but a iauch 1 m uch better one than has ever been placed upon the market we believe we have accomplished what we started out to do and feel confident that the pinder concentrator is all we w e claim for in this machine all the valuable features of the plain corrugated or rif fled tables have been preserved and greatly improved upon every known scientific principle is at work jigging suspension in and dressing by the cross flow of water it occupies less floor space takes less power to drive it and costs less for transportation por tation charges than any other concentrate THE PINDER concentrator ing table made it will work much better with less expense with less attention pro during more salable products and in point of excellence of work quantity variety simplicity city efty durability and cost there is nothing inthe on the market to compare with it it is our desire to particularly point out to the mine owner and mill man that this machine iachine takes advantage of the law thatis that if bodies of equal volume and of different specific gravities are dropped at the same instant from the same height into a volume of water vater the one of greater weight will wil sink faster fasier than the other leaving it behind and arriving first at the bottom this principle allows the converting of low grade ores into lil nigh grade concentrates for all the baser minerals 19 have a greater specific gravity than the rock which carries them and in order to effect a saving of these values it is necessary to have a machine which can be so adjusted that the least variation in the specific gravity of the materials will cause the particles tiel les to separate from each other the heavier particles to be cleaned from the aig lighter ahter gangue which contains it the important feature that distin the pinder finder concentrator from all others is its batea or pan shaped top made in the form of an with its outer edge curving inward from the receiving end of the feed box the concentrating surface of which is provided with spiral tapering riffles fiffles that are a novelty and constitute the essential element of the success of the machine this idea is entirely new and dispenses with the necessity real or supposed of returning the product to the feed box for if the material is carried round and round and across the table by the same route the principal effect will be a reduction of the tables capacity by just the amount of the tailings returned we copy not only the form and principle embodies in the gold pan but als also 0 its movements in the most perfect manner and being mechanical its operation is absolutely perfect to understand the condl condi eions under which the pinder finder concentrator operates in order to extract the constituents of a slime from the accompanying compa nying particles of rock or gangue it will be worth while e to watch the process of where the muddy water is kept in gentle motion for some time by the circular movement of the pan until the almost impalpable mineral slowly settles to the bottom while the comparatively coarse particles of mixed rock and mineral are caused to move forward by a succession of jumps the motion is now interrupted for a short time to alow allow a further settling oi of the material when a gentle wave of water is caused to flow repeatedly over it washing the fine rock across the pan away from the mineral as the metallic ores being of greater specific gravity withstand better the flow of water this fine mineral can not be thrown forward as was first described as it has not the weight or body but is separated from the sand by taking advantage of the greater grade of sulphides sulp hides the more friable they are and the finest slip sli paes leg in most ast easily easil y affected by agitation carry the richest particles reaching a culmination in the bellu rides the importance of saving the highest possible percentage of these values depends on the grade of the ore as in many cases it costs more to save the finest concentrate than the total tortal amount saved then it becomes necessary to handle a larger quantity and pay little attention to the additional loss in tailings some distinction should be made between the terms concentrates fines and slimes in general it may be said that concen concentrates are the particles saved coarser than mesh in size fines between and mesh and settling in water quickly while slimes are in a still finer state of division and are held in suspension in the water or float on top settling only after long standing slimes are always more difficult to treat than the coarser particles and are collected only by adhesion or cohesion as the mineral in its finely f divided state flows off readily in a stream of water and refuses to settle away from the accompanying gangue if dry streaks or points occur the water as a consequence runs in streaks and at the junction of the wet and dry channels mineral will wili be picked up and floated away on the surface of the water this floating of the mineral is caused by its dryness not by its lightness it has been coated with a film of air is a term used to describe part particles idles of gangue firmly united with minute particles pAti cles of ore ord a product sometimes obtained in the process of concentration it is common practice to return this product to the h head ead of the table but as the ultimate object to be attained by concentration is the separation of the mineral mineral from the gangue the procedure is useless for the second effort at concentration simply repeats the first process and will be of no avail unless it includes re crushing to further liberate the he mineral particles that it contains co the tendency of a mixture of ore particles of approximately similar size but of varying vary inga specific gravities is to arrange itself in layers according to gravity when given motion another important feature on which concentration is based is that thorough settling precipitates the heavy base mineral and sulphides sulp hides to the bottom leaving the lighter on top with any other material too low in grade to pay for further treatment being run to waste if chlorides are present in sufficient quantities they can be saved at small expense by leaching or amalgamation without roasting the concentrates if rich enough are shipped without further handling but it is found occasionally to be of benefit to cen them over another table running at slower speed and increased grade in this case two machines of the same type are used the concentrates conc a tes of the first passe ing directly to the second with some ores it is advisable to the tailings from the first operation in order to further save the portion of the slimes which may contain sufficient values to warrant the addition expense the ores that are incapable of concentration are carbonates and silicates of copper without sulphides sulp hides copper and pyrite which may contain gold and silver without silica iron pyrite heavy all other ores can be worked either eichler by plain concentration or by a combination in which wet extractions enter it being possible to save in copper 70 to 90 per cent conundrum Corun drum 75 to 85 per cent garnet 60 to 80 per cent gold 85 to 95 per cent iron 75 to 95 per cent lead 90 to 95 per cent silver 60 to 90 per cent tin 85 to 95 per cent wolfram 80 to 90 per cent zinc 50 to 92 per cent |