A Story Of Lead (1948)

[Music] [Music] [Music] in the lead belt of Southeastern Missouri the largest lead mining operation in the United States has been carried on since 1720 the original operation was French American interests have dominated the mines since the Louisiana Purchase in 183 the lead Bel lies in the foothills of the Ozark Mountains within 65 miles of St Louis an outstanding feature of the lead belt the huge chat piles left from the millions of tons of lead removed in past years chat is the crushed rock from which the lead has been extracted arriving at the mine the men change to their working clothes in change houses provided with individual lockers showers and washrooms loading of the mine cage at the shaft is regulated by safety measures only a specified number of men for each cage in the loading zone at a time each minor must be equipped with a safety hat hard toed Footwear and a lamp 400 ft below the surface the miners reach the main H level M Passenger cars called Cy cars transport them to their working areas the 24in gauge track is electrically welded such welding is possible because the uniform yearround underground temperature of 60° eliminates problems of expansion and contraction the worked out areas now serve for the location of the main hauling system and provide wide ample clearances along the right of way with plenty of headro for the overhead trolley wire when underground mining was started the shaft was sunk directly into the ore body now mining is carried on by the ruined pillar method as the work progresses removal of the ore leaves large open rooms in order to better understand the operations let's look at this animated drawing first The Ore bodies are located by The Diamond Drill from a nearby shaft the miners cut a drift to reach the or bodies the path of the drift is carried on at a rate of 8 to 10 ft per day by successive rounds of drilling blasting and removal of the M pneumatic drills bore approximately 28 blast holes 9 ft deep to each round wet Drilling and proper ventilation minimize Rock Dust water is forced through the machine and the hollow steel drill to the bottom of the drill hole the holes are loaded with about 200 scks of dynamite cap wires from all the holes are then connected in series and hooked up to a Magneto blasting machine which which detonates the charge after 4 hours natural ventilation has cleared the mine of smoke a mechanical loader or shovel removes the broken rock from the drift depositing it in the mine car at the back of the loader the mine car shown is coupled to the loader and moves back and forth with it this prevents filling of the rock a train load of waste cars is made up and hauled to the near waste rock shaft where the rock is hoisted to the surface for disposal the lead ore called Galina a sulfide of lead is found embedded in Limestone and is seen as shining particles the Southeastern Missouri lead district is one of the few areas where no other metals are associated with the lead to any great extent in hundreds of stapes scattered through the mines miners are drilling holes into the ore in preparation for blasting wet drilling is employed in all types of mining throughout the lead belt in this operation the pneumatic drills are mounted on columns and connected with an air feed which advances the drill against The Rock after the drill holes are loaded with dynamite the explosives are detonated by lighting the fuses with a timed sparkler which ensures proper time allowance for the lighting of all drill holes the actual blast cannot be photographed 4 hours after blasting which allows for the clearance of smoke and gases Drillers and Foreman conduct a thorough inspection of roofs and walls to remove any loose or hanging materials broken ore is loaded into mine cars by electrically operated loading machines capable of loading all of the ore broken during an 8 hour shift this often amounts to 100 cars a loading machine is Almost Human in its responsiveness to the delicate controls this mechanism is of the self-contained Caterpillar tractor type and can be moved under its own power to new locations nobody knows exactly how much lead has been recovered from the lead belt mes in the last 200 years some of course was mined under the French beginning in 1720 except for brief intervals mining operations have been almost uninterrupted since that time these high cleaned out soaps constitute the most impressive visible evidence of past operations following the horizontal body of ore miners have drilled and cut and blasted for decades yet nowhere will one see a single piece of Timber support the aftermath of all this work is found in great catacomb like Chambers nearly 200 ft high in places how much ore remains in the lead belt no one knows but the region is now and for years to come promises to be the foremost producer of lead in the United States miners become as skilled as trapes artists working on high platforms suspended from the roof scores of feet above of the floor of the Stoke skilled miners swing back and forth on the walls of The Stoke scaling down loose and hanging material to make certain that there's no loose rock or other threat to the safety of the men below with constant Improvement or is being mined today that would have been impractical in the past miners drilling high in the roof are protected from falling by the wearing of safety harnesses fasten to the platform safety is the a Paramount consideration at all times as drilling progresses the work is carefully inspected by the foreman in these large stapes prospecting and Mining is continuously carried on large Boulders are drilled and blasted to facilitate removal of the ore while surveyors measure the soap and gather data to keep mining Maps up to date through vast underground Cathedrals ore trains go to the shf where the ore will be hoisted to the surface it's hard to realize that man has carved these gigantic soaps with their massive pillars so similar are they to the Fantastic forms carved by Mother Nature and the elements through the centuries but it was the persistent Toil and Ingenuity of the miner working in darkness by the flicker of a small Miner's lamp which created these Royal Gorges electric locomotives hold trains of 25 to 50 cars as much as 6 miles inside the mine and at speeds of 9 or 10 m hour prior to dumping the entire or train passes over automatic scales that weigh each car as it passes without uncoupling this complete railroad terminal located 400 ft underground with heavy trains arriving every few minutes and departing empty May well be likened to that of a great City at the bottom of the or shaft are located the rotary dumps the cars are dumped into the OR pocket three at a time without uncoupling from the Rotary dump the ore falls into the skip pocket and slides to the skip loading shoot which are equipped with hydraulically operated Gates these enable the skip loading operator to control the flow of ore into the skip an or skip is loaded approximately every 30 seconds that's a rate of 100 skip per hour skips are hoisted to the surface at a speed of 12 to 1500 ft per or is dumped into bins from which it's transported to primary Crushers surrounded by huge chat piles five large crushing concentrating and flotation Mills are located at the or hoisting sha to handle the 22,000 tons of crude ore that are brought to the surface every 24 hours the Run of mine ore flows to these large drum feeders which maintain a constant feed to the primary Crusher dry crushing is performed in three stages to prepare the ore for further treatment and recovery of its lead content in the first stage the primary gyratory Crushers break the ore to fragments about 3 Ines in maximum size The Ore then goes to the secondary Crushers for further reduction in size on Route it moves under a large electromagnet which removes fragments of steel or iron after passing through Dry vibrating screens The Ore is transferred to the main storage bins at the head of the concentrating no at the top of the conveyor is a device which automatically takes samples at regular intervals from the analysis of these samples and from the record of all tonnage it's possible to determine the amount of lead contained in the ore which comes to the mill each 24 hours at the top of the mill the dry crushed ore is conveyed to a spreading machine called a Tripper which travels over the top of the ore bins and distributes The Ore they Tripper divert The Ore stream from the conveyor belt into compartments representing the main or bin separation of the lead mineral from The Ore begins with the elevation of the pulverized or or from the storage bins water is added and the wet pulp discharged in gathering boxes from which it flows to wet screens vibrating screens separate the pump into oversizes and undersiz the oversiz which flows over the screen is sent to the rod Mills to be further reduced the UND size passing through the screens goes to the classifiers the oversize is ground in Rod Mills which turn at the rate of 18 Revolutions a minute it's fed to the mill with enough water to prevent over grinding or is pulverized by the tumbling of the rods as the mill revolves in the hydraulic classifiers the Sands are separated into 30 different sizes of these the finest are the slimes which overflow here and are next sent to another part of the plant for treatment by the flotation process the different sizes of classified Sands are treated on concentrating tables to separate the lead from the weight the various sizes are treated on different tables sized ore from the classifier is introduced at the head end clear water flows constantly over the deck the motion of the deck causes the Galina indicated by the dark area to separate from the waist and discharge from the end of the table long narrow strips of rubber called ripples divert the mineral particles at the same time the waste flows over the riffles and discharges from the Sid thereby separating the minerals from the waist and yielding three products one a lead concentrate two a low grade product called midling which is returned to the grinding circuit and three a product called tailings tailings and waist from the flotation machines are electrically pumped to the tailing pond the dewatering of the mineral product of the concentrating tables is done by a vacuum filter and dewatering drag the wet pulp is fed to the filter a vacuum pump draws the water through a porous filter blanket leaving the lead concentrate adhering to the blanket as the filter rotates an automatic valve periodically releases the vacuum dropping the dewatered lead concentrates into a hopper the concentrates are then elevated to storage bins later to be shipped to dis smelter slime from the dewatering machines is pumped into a mixing tank where chemicals are added the chemically treated slime is next pumped to flotation machines the or pulp enters the machine and is continuously agitated by air the air agitation together with a chemical collecting the agent causes the formation of a fro which Rises to the top of the pulp and overflows due to the presence of a collecting reagent the minute particles of lead mineral are induced to adhere to the bubbles thus lead mineral Rises out of the pulp and overflows the lead bearing fro from the air flotation machines is subjected to recing in which the agitation is affected mechanically instead of by air flotation concentrates from these machines assaying over 70% lead are sent to the filtering and drying plant for dewatering after thickening the concentrates from the flotation machines are prompt to revolving drum vacuum filters by application of vacuum the lead concentrates are held to the face of the filter drums and th watered then the vacuum is released and the mechanical scraper removes the filter cake this filter cake contains about 133% moisture which is too wet for shipment to the smelter so it's further dried by passing through a gas fired cylindrical dryer the dried concentrates are dropped into a belt which conveys them to a loading machine a typical grain loading machine deposit the concentrates in box cars this mechanical loader enables uniform distribution of the concentrate in the car at herculanum Missouri 35 miles from the mines and Mills is located a smelter which has been in Daily operation since 1893 here the high-grade concentrate from the Mills receive their final processing every day long trains of box cars containing the concentrates arrive at the smelter from each car samples are taken for assay to establish its moisture content and the exact percentage of lead the plant laboratory also maintains close control of smelting operations scoop graan unloaders are used to unload the ore into mixing bins where fluxes will be added all the fine materials around the plant go into the centering mixture additional fluxes are limestone silica sand iron oxide and granulated slags the collected fluxes and concentrates are delivered by conveyor to a huge pan where they're thoroughly mixed pallets carry the mix under gas fired burners during this slow process ignition takes place from above suction fans create the necessary drafts in a downward Direction Through the pallets of Center mix the method of igniting the mix may be likened to a man lighting his pipe and drawing air through to keep the tobacco burning the smoke and fumes pass downward through the pipe Bowl similarly the gas burners ignite the sulfur in the mix the suction of the fand draws smoke and fumes down through the center bed the fumes are collected and treated for the recovery of lead content burning for 10 to 15 minutes reduces the sulfur content leaves the pallet in the form of a porous cake or clinker which is cooled by a water spray from the pallet the steaming hot Center cake passes over a Grizzly and is dumped into a car for delivery to the crushing plant through the openings of the grizzly bars the finer material passes to a hopper and then to a conveyor which carries it to storage bins where it's kept in Readiness for the final roasting after which it may be smelted underneath the blast furnace bins an electrically operated l car collects the various fluxes required for the charge the charge foral smelting in the blast furnace consists of Center Coke and slag when the charge has been collected the Larry car runs over a pit and drops the charge into a blast furnace charge car below after the transfer is completed the charge car is elevated to the charging floor of the blast furnace building the blast furnaces require periodic relining they're 20 ft high with a hearth 50 in wide and approximately 16 ft long the hopper of the charge car electrically operated by remote control is rotated and dumped into the top of a furnace the blast furnaces are operated continuously in 3 8 hour shifts 7 days a week furnaces are provided with inlets which admit the oxygen for burning the coke air is forced by large blowers through a bustle pipe to the inlets and then upward through the charge flag is tapped from the furnace intermittently the heavy lead metallic and mat are combination of other metals with sulfur settle on the bottom of the heart while the lighter waste product or SL FL flows over the top and into the slag pot at the side of the forar the mat is tapped from the bottom and flows into a matte pot and this is then transported to the granulator mat is a combination of copper nickel iron and Lead sulfide in molten form it's poured into a high press water stream the force of the water the sudden change in temperature solidifies the M into small particles which are sold for their metal values each furnace produces 200 tons of crude lead every 24 hours this after processing in the refinery yields 150 tons of refined lead suitable for Market from a furnace the lead is taken to a dring wheel where part of the dross is removed dross containing such impurities as copper and nickel along with a high percentage of lead is skimmed off with a large Ladle it's poured into moles to form rough pigs which will again be run through the blast furnace to recover their lead content after this preliminary skimming of the draw the lead is taken to the refinery for the further elimination of its impurities the lead pot is hoisted by an electrically controlled crane which is operated from the floor and the metal is poured into the rough droing Kettle a perforated Dro basket with a capacity of 3 and 1/2 tons is immersed in the kettle skimming off the draw the basket is hoisted by the crane and suspended above the kettle while the metallic lead drains back a centrifugal pump is inserted under the small remaining quantity of the draw and serves to pump the metallic lead to an adjoining Kettle different types of lead are made according to the uses for which the metal is intended here the remaining drao is removed and the leads allowed to cool to 625 de F this is called chemical lead other types of lead are made where it's necessary to remove the silver to improve the purity of the lead zinc is added to the metallic lead in the refining process for the removal of silver the zinc Alloys with the silver then floats to the top and is skimmed off this beautiful seal the great state of Missouri is made entirely of silver recovered from refining Missouri lead designed by the distinguished American sculptor Paul manship it has been donated to the Battleship Missouri the also removes whatever copper and nickel are left in the lead after removal of the silver the lead is pumped into a gas fired furnace for removal of the 61% of zinc which has been left in the course of the desilvering process pure lead from the desyncing furnace is pumped into a holding Kettle for partial cooling then it's piped to the casting wheel where it's poured into 100b Pig the metal flows through a pipe supported by a harness over the operator's shoulders this operation calls for the skill of a three armed man as the Workman Pours and simultaneously skims the metal with paddles in both hands rotation of the casting wheel is electrically controlled by the operator the filled molds pass through a continuous spray of cold water applied at top and bottom to cool the lead an automatic marking device stamps the ident or production number on each Pig five at a time the 100 PB pigs are plucked from the casting Wheel by an ingenious device called a pck which operates by compressed air with each load the p is swung around and the pigs are stacked in piles seven High the lead pigs are cast with protruding ears to facilitate handling in shipment an electrically operated lead loading buggy picks up the 3 500b stack of pigs lifting them by the ears and transport them to the weighing scales after which the metal is transported by electrically operated loaders and delivered to Freight cars on the refinery sidings when each car loaded to its capacity of about 50 tons the metal lead is sent out to the many various Industries to be converted into useful article for mankind this pig of lead weighing 100b has been obtained from the smelting of about 138 pounds of concentrat which by Milling have been produced from approximately 3,300 lb of ore taken from the Mes in the Milling process about 3100 lb of almost leadfree Limestone was discarded as waste locally called chat the industry consuming the largest tonnage of American lead is the automotive industry almost every car uses lead in storage batteries solder and bearing Metals needed in brake linings in addition lead is used in gasoline for better performance lead storage batteries are also widely used in airplanes submarines industrial Lift Trucks power plants farm and car lighting and mine locomotives and humble lead also plays its part in preserving and protecting old and new buildings in the form of white lead for wooden structures and red lead for seal lead plays a vital part in electric power transmission and in telephone communication as a protective sheathing for electrical conductors lead's also extensively found in Plumbing Systems and in the chemical industry wherever sulfuric acid is made or used lead has many other uses far too numerous to detail here such as ammunition tight metal foil collapsible tubes insecticides and sinkers such is the story of an American mining Community monuments to the tireless industry of many decades the great chat piles whose volume is considerably larger than the pyramids Bloom against the sunset a record of achievement and the hint of the wealth still buried in the lead belt of Southeastern Missouri [Music]

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Length: 27min 48sec (1668 seconds)

Published: Wed Sep 05 2012