Quarry By-Products

Screenings are uniformly sized, fine, sandy materials with some silt particles. Screenings commonly range in particle size from 3.2 mm down to finer than 0.075 mm. Normally, the amount of particle sizes finer than 0.075 mm is 10% or less by weight. Stockpiles of screenings may contain some particles up to 4.75 mm in size, which is usually the screen mesh size used for separation. Some weathered rock or overburden material may be present in the screenings from certain processing operations. 

Pond fines, when initially recovered from the pond, consist of a fine-grained slurry with a low solids content, usually with 90-95% of the particles finer than 0.15 mm and 80% or more of the particles finer than 0.075 mm. Although particle sizing may vary somewhat with fines from different types of stone, the range in particle size of baghouse fines is from 0.075 mm down to 0.001 mm or even finer. 

There is very little difference in the chemistry or mineralogy of screenings and pond fines from the same quarry or rock source, and also very little difference in the chemistry within the size fractions of the pond fines [149-151]. 

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Carpet fiber dusts 1.2 million t (1.32 million T) 14 Quarry by-products QBP 3.6 billion t (4 billion T)... 

Wood SA, Charles RM (1993) Recovery and utilization of quarry by-products for use in highway construction. Proc Symp on Recovery and Effective Reuse of Discarded Materials and By-Products for Construction of Highway Facilities. Federal Highway Administration, Denver, CO, p 469... 

Fluorine never occurs as a free element in nature. The most common fluorine minerals are fluorspar, fluorapatite, and cryolite. Apatite is a complex mineral containing primarily calcium, phosphorus, and oxygen, usually with fluorine. Cryolite is also known as Greenland spar. (The country of Greenland is the only commercial source of this mineral.) It consists primarily of sodium aluminum fluoride (Na3ALF6). The major sources of fluorspar are China, Mexico, Mongolia, and South Africa. In 2008 in the United States, fluorspar was produced as a by-product of limestone quarrying in Illinois. The United States imports most of the fluorspar it needs from China and Mexico. 

Quarry byproducts (QBP) Mineral filler - The only quarry fines by-product that would require significant processing for any of the foregoing applications are the pond fines, which would have to be adequately dewatered before use - Pond fines would require a greater degree of dewatering for use as mineral filler in asphalt than for use in flowable fill 149-150... 

The main raw materials used in the cement manufacturing process are limestone, sand, shale, clay and iron ore. The main material, limestone, is usually mined on site while the other minor materials may be mined either on site or in nearby quarries. Another source of raw materials is industrial by-products. The use of by-product materials to replace natural raw materials is a key element in achieving sustainable development. 

Energy sources used in the clay brick making process worldwide are dominantly derived from fossil fuels. However, through innovative development it has been shown possible for these traditional sources to be successfully replaced by renewable alternatives reducing greenhouse gas emissions to almost zero. In a further iimovative step, it has been possible to introduce a selective blend of solid by-products wastes into the manufactured bricks to partially replace normally quarried cl. ... 

Limestone Production. Because more than 99% of U.S. limestone is sold or used as cmshed and broken stone, rather than dimension-stone, most of the description of limestone s extraction and processing herein focuses on the former (Fig. 4). Most stone is obtained by open-pit quarrying methods. Underground mining is pursued by some important operations, but the toimage quarried exceeds that mined by nearly 20-fold. There is, however, a slight trend toward increased mining which should continue. 

The first commercial shipment of diatomite ia the United States was made ia 1893 and consisted of material from a small quarry operation ia the vast deposit near Lompoc, California. It went to San Francisco to be used for pipe iasulation. Small-scale operation of parts of the Lompoc deposit continued until it was acquired by the Kieselguhr Co. of America, which later became the CeHte Co. (4). Siace that first work, the iadustry has grown immensely, and diatomite products are used ia almost every country. 

Crushed Stone and Aggregate In-pit crushing is increasingly being used to reduce the rock to a size that can be handled by a conveyor system. In quarries with a long, steep haul, conveyors may be more economic than trucks. The primaiy crusher is located near the quariy face, where it can be suppRed by shovels, front-end loaders or trucks. The crusher may be fully mobile or semimobile. It can be of any type listed below. The choices depend on individual quariy economics, and are described by Faiilkner [Quairy Management and Products, 7 6), 159-168 (1980)]. 

The major purposes of comminution or size reduction operations can be summarized in four categories as shown in Table 2.2. Comminution is almost invariably performed in two or more stages. It starts with the crude mined or quarried product this is progressively taken to the desired final size by a step-by-step process. As the process of fracture is involved throughout this procedure, a brief discussion on the fracture of materials is appropriate at this point. 

Excipients are produced by a diverse group of manufacturers who range from pharmaceutical companies to specialty chemical manufacturers, food producers, and even mineral quarries. These manufacturers are involved in a diverse range of chemical processing and usually produce excipients as a small component of their product mix. 

Mineral product companies also provide excipients to the industry. Such companies may produce these inorganic chemicals by quarrying rock and separating the desired chemical entity such as talc, sodium chloride, or sodium carbonate. Alternatively sometimes the inorganic excipient is produced synthetically. The market for excipient grade minerals is dwarfed by other applications for these products in the industrial market. 

Another expl consisting of prilled AN fuel oil and supplied by the DuPont Co is the ANFO-P, which is a free-flowing product of density 0.75 to 0.85g/cc. As the fuel (or diesel) oil of this expl is volatile and of sharp odor, the mixture is not recommended for underground work, but its major application is in large quarry biasring (Ref 8, p62)... 

Ammonium nitrate prills are often mixed with fuel oil (liquid hydrocarbons) to produce a commercial explosive mixture known as ANFO which is used in quarrying. ANFO can be prepared in a factory by mixing both ingredients in a rotating container and dispensing the product into polyethylene or cardboard tubes. The tubes are then sealed and transported to the place of use. ANFO can also be prepared at the site where the explosive composition is to be used. Fuel oil is poured into a polyethylene bag containing ammonium nitrate and left for some time to allow the oil to soak into the ammonium nitrate. The ANFO mixture is then poured from the polyethylene bag into the hole (i.e. shot-hole) where the explosive mixture is detonated. 

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