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Using Wastewater Solids to Reclaim Strip Mined Land

To protect the water supply for the Metropolitan Chicago area, the Illinois legislature, in 1889, created the Metropolitan Sanitary District of Greater Chicago. To insure the quality of the water supply, the Sanitary District collected and diverted the wastes of 750,000 people away from Lake Michigan. Today, the Sanitary District collects and treats the wastes from a domestic population of 5% million people and an industrial waste load equivalent to 4% million people. The District serves Chicago and 120 other cities and sub-urbs in an 858 square mile area.

Discussion

The wastewater enters the treatment plant through underground sewers, some as large as 24′ in diameter. The wastewater passes through screens which remove coarse debris such as rags, branches, bits of wood, etc. before being pumped to ground elevation. After pumping, the wastewater flows by gravity thru grit tanks which remove grit and sand particles by sedimentation. After grit removal, the wastewater flows into a primary settling tank where from 40% to 50% of the organic and inorganic solids settle out and are pumped to anaerobic digesters. The wastewater then flows to aeration tanks where it is mixed with another flow containing microorganisms which feed on the organic matter remaining

Similkameen Tailing System

The Similkameen Copper Project located near Princeton, British Columbia, is operated by the Similkameen Mining Company Limited, a wholly-owned subsidiary of Newmont Mining Company. The orebodies for this project are located on both sides of the Similkameen River for which the project is named.

The Pipeline Tunnel

To complete a tailing line routing to Smelter Lake, a tunnel with clearance dimensions 10 feet wide by 8 feet high approximately 800 feet long was driven where an area of sheer cliffs blocked access. The tunnel was driven on a downward slope of 1 percent in the direction of tailing flow so that any leakage of tailing would flow naturally into the impoundment area and eliminate this portion of the line as a possible source for escape of tailing into streams. A suitable location was found which provided an adit elevation about 100 feet below plant discharge elevation.

The tailing pipeline material chosen was 20 inch spiral-weld abrasion resistant steel with ¼ inch wall thickness in 40 foot random lengths equipped with end fittings for assembly by wedge-lock couplings. The pipe has a minimum Brinnell of 170 having an approximate analysis of 0.70 percent Mn, .015 Si, 0.50 percent C. Under normal rating,

Synthetic Zeolites Properties and Applications

Zeolites were first recognized as a new group of minerals by Cronstedt with the discovery of stilbite in 1756. The word zeolite was coined from the two Greek words meaning “to boil” and “a stone” because of the loss of water when heated in the mineralogist’s blow pipe.

In 1845 it was discovered that certain soils have the power of retaining ammonium salts. These were the first ion exchange experiments. Later it was discovered that it was the hydrated silicates in the soil that produced this phenomenon and several years later a paper was published dealing with the action of dilute salt solutions on silicates which showed that this base exchange principal, which we now call cation exchange, is reversible. The quantitative cation, exchange behavior of zeolite minerals, such as chabazite, was studied.

Zeolite Structural Chemistry

Along with the feldspars the zeolites are framework silicates; their structures consist of a three-dimensional framework of SiO4 and AlO4 tetrahedra. As in the feldspars the trivalent aluminum in these tetrahedral positions requires the presence of additional positive charge such as alkali metal or alkaline earth ions in order to maintain electrical neutrality. In the zeolites, for stability reasons the maximum substitution of aluminum for

The Syngenetic Massive Sulphide Deposits

The large massive sulphide deposits present a formidable challenge to the economic geologist. They represent such huge concentrations of iron, sulphur, base metals and precious metals that it is difficult to conceive how they were derived from the crust or mantle of the Earth. The problem of the origin of massive sulphide deposits has generated a geological controversy which has lasted two hundred years and shows no sign of abating.

Field Evidence of the Origin of Massive Sulphide Deposits

Although much experimental and theoretical work has been done towards elucidating the origin of the massive sulphide deposit, the most significant advances have come from field observations, particularly those made by geologists whose activities have permitted them to see many deposits.

It is beyond the scope of this paper to describe all of the characteristics of the massive sulphide deposits found in volcanic and sedimentary rocks. The four characteristics described in the following pages have been selected as having a particular bearing on the origin of the deposits.

Lithologic and Stratigraphic Associations

Massive sulphide deposits show certain marked regularities in their stratigraphic and lithologic associations. These relationships appear to be consistent, regardless of the age of the deposit. Geologists whose experience has

Shaft Kiln for Lime Production

New is a relative term, and when used with reference to a concept as old as shaft kilns can be applied to a number of designs. In this case the design that is the subject of this paper, is known as the ring or annular shaft kiln as developed by Mr. Karl Beckenbach of West Germany.

It is a single vertical cylinder to which are attached the required service platforms, combustion chambers, injectors and distribution piping. Auxiliaries such as recuperator, exhaust fan and dust collector are mounted on the appropriate service platform. The charging pan, feed conveyor, etc. are mounted at the kiln top. At the bottom of the kiln is the silo with a vibrator type discharger, and mounted separately is the required blower for injector air and fan for internal cooling.

Material flow begins with the stone being fed to the charging pan by conveyor. The charging pan is in the form of a ring mold and is rotated while being filled to insure an even distribution of stone sizing being fed to the annular space in the kiln. When the pan is loaded, the conveyor is withdrawn and the pan cover lowered into place. Next, the bottom of the

Semi-Autogenous Liners

The never ending search for lower unit costs led Pima Mining Company’s management to study various alternatives shortly after Expansion III was completed. It soon became apparent that a considerable amount of ore assaying 0.35% copper had to be moved in order to maintain mill feed at the desired 0.54% copper content.

New Mill Flowsheet

A completely new and separate primary crusher was constructed for Expansion IV. The new primary is identical with the existing one except that the crusher discharge is fed to a Barber-Green radial stacker conveyor that can serve both the old mill stockpile and the new mill stockpile.

The minus eight-inch primary crusher product is reclaimed from the stockpile by four 42′ wide by 12′ long NICO pan feeders. The grinding circuit consists of two identical sections that can be used as separate circuits or combined.

Pan feeder discharge is conveyed directly to the two 28′ diameter by 12′ long Koppers semi-autogenous mills. Each mill is driven by dual 3,000 HP wound rotor motors through Falk reducers, resulting in a total connected horsepower of 6,000. Mill speed is 10.95 rpm. or 75% of critical. Mills are loaded with 6-8% by volume of 4″ forged steel grinding balls. The

Remove Sulfur Dioxide from Off Gases of Coal Burning

The purpose of this article is to present design information and operating data on a pilot gas scrubber which is believed to be a new approach for removing noxious gases and particulate matter from the off gases of coal burning power plants and smelters.

In addition, gas scrubbers on stream or being developed for coal burning power plants and smelters have other undesirable aspects such as high pressure drop requiring high operating horsepower, relatively low gas velocities, demisting problems, and the production of slurry discharge, relatively low in solids content. This last places extra burden on settling basins, lagoons or mechanical dewatering equipment. Our design attempts to eliminate some of these undesirable aspects of gas scrubbers and to minimize others. Our concept is based on the following premises:-

  1. Particulate matter cannot adhere to a moving surface which is continuously bathed by a moving liquid.
  2. Low pressure drops across the scrubber will be achieved if the gas flow cannot pass through the aqueous scrubbing medium.
  3. Impingement of these gases and particulates on liquid surfaces is an efficient scrubbing procedure for the minimization of mist.
  4. The ability to control retention of the aqueous scrubbing medium within the scrubber independent of gravity and of

Pebble Grinding

The operations of Bethlehem Copper are situated in the south-central interior of British Columbia at an elevation of 4900 feet above sea level. Main road and rail transportation systems pass through Ashcroft in the Thompson Valley, which is 28 miles by road from the minesite. The operation was the first low-grade open-pit porphyry copper mine in British Columbia

A cheaper method of grinding was necessary and information was collected to assess the feasibility of pebble grinding, This study showed a higher capital cost, lower operating cost, and substantially increased revenue from copper contained in pebbles consumed. The calculated return on investment was attractive and arrangements were made to pilot the operation at the facility of a mill manufacturer to assure the reliability of the figures being utilized.

Pebbles are conveyed on 18″ conveyors to a 1,000-live-ton cylindrical storage bin. Load level is measured sonically and the signal transmitted to the crusher control room for readout. Pebbles are fed from this bin by vibrating feeders to 18″ conveyors which in turn feed the two pebble mills.

The two 16.5′ x 32′ grate discharge pebble mills are driven by low-speed synchronous motors through air clutches and single helical gearing at 69% of critical speed. Babbitt

Open Pit Equipment Selection and Maintenance

Principal factors influencing equipment selection can be grouped into five basic categories. Tonnage Requirements, Ore and Waste, Topography and Property Line Considerations, Ore Control Requirements, Physical Characteristics of Ore and Waste, and Climatic Conditions.

Site Preparation

Specialized Machines: This type of equipment generally operates on the principle of leverage uprooting and mechanical breakage of fallen vegetation. It is used in areas where little or no revenue can be derived from the sale of the vegetation removed.

Bulldozers – Crawler, with Special Attachments: Attachments available for this type of clearing equipment are: brush rakes, stump plows, rippers, demolition and multi-purpose buckets, and grapples. Vegetation is usually uprooted, then dozed into convenient piles for removal or burning. The most economical dozing range for this type of trash cleanup is a distance of 100 to 150 yards.

Drills – Jackhammers, Airtracs: These units are principally used in the process of building drill roads or in blasting of surface boulders.

Bulldozers – Crawler: These units are confined to preparing a level surface to support large rock drills, rock breaking equipment, or loading equipment. The larger bulldozers are generally equipped with rippers and tilt blade for use in building drill roads in rocky or mountainous terrain.

Drills – Large Diameter (Percussion): Since these drills

Mobile Crushing Plants

The transportation of mine products incurs a cost which can have a significant bearing on the competitive position of the product. This statement not only holds true for the transportation of the finished product but certainly as much for the in-plant haulage of the raw materials.

First of all, it should be differentiated between 3 categories of movable equipment.

a) The idea of a PORTABLE crusher is not new. Many such wheel-mounted installations are available but their size and capacities were mostly limited to 500 or 600 tph. Portable plants can be relocated -even over the road- from one quarry into another by simply hooking them on a trailor-truck.
b) Larger units can be mounted on skids or rail and are known as SEMI-PORTABLE. In some cases they require extensive preparation or partial dismantling for a relocation and are, therefore, used in mines or quarries where frequent relocation is not required.
c) As the word MOBILE already indicates, these plants move under their own power and may be mounted on crawlers or walking pads.

Loading costs are certainly also reduced by the use of movable precrushers since, according to Kochanowsky the volume loaded per hour by the shovel can be increased by as much as 50%

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