A stacker is a large machine used in bulk material handling. Its function is to pile bulk material such as limestone, ores, coal and cereals onto a stockpile. A reclaimer can be used to recover the material.
Gold dredges in Alaska had a stacker that was a fixed part of the dredge. It carried over-size material to the tailings pile.
Stackers are nominally rated for capacity in tonnes per hour (tph). They normally travel on a rail between stockpiles in the stockyard. A stacker can usually move in at least two directions: horizontally along the rail and vertically by luffing (raising and lowering) its boom. Luffing of the boom minimises dust by reducing the distance that material such as coal needs to fall to the top of the stockpile. The boom is luffed upwards as the height of the stockpile increases. Some stackers can rotate the boom. This allows a single stacker to form two stockpiles, one on either side of the conveyor.
Stackers are used to stack in different patterns, such as cone stacking and chevron stacking. Stacking in a single cone tends to cause size segregation, with coarser material moving out towards the base. In raw cone ply stacking, additional cones are added next to the first cone. In chevron stacking, the stacker travels along the length of the stockpile adding layer upon layer of material.
Stackers and reclaimers were originally manually controlled, with no means of remote control. Modern machines are typically semi-automatic or fully automated, with parameters remotely set. The control system used is typically a programmable logic controller, with a human-machine interface for display, connected to a central control system.
Other than stacking, a stacker has three basic movements:
The conveyor belts used in stackers may be made of fabric or metal wire, depending upon the material to be handled. They are driven by pulleys, which in turn are driven by DC motors. The motors and gear are coupled by fluid coupling.
Most stackers are electrically powered by way of a trailing cable. There are basically two types of cable trailing: power cord rotating drum (PCRD) and control cable rotating drum (CCRD). Pendulum adjustments are made to ensure the proper alignment of these cables while the stacker is travelling.
A clutch is a mechanical device that allows an output shaft to be disconnected from a rotating input shaft. The clutch's input shaft is typically attached to a motor, while the clutch's output shaft is connected to the mechanism that does the work.
A pulley is a wheel on an axle or shaft enabling a taut cable or belt passing over the wheel to move and change direction, or transfer power between itself and a shaft. A sheave or pulley wheel is a pulley using an axle supported by a frame or shell (block) to guide a cable or exert force.
Excavators are heavy construction equipment primarily consisting of a boom, dipper, bucket, and cab on a rotating platform known as the "house" - although the largest form ever, the dragline excavator, eliminated the dipper in favor of a line and winch.
A crane is a machine used to move materials both vertically and horizontally, utilizing a system of a boom, hoist, wire ropes or chains, and sheaves for lifting and relocating heavy objects within the swing of its boom. The device uses one or more simple machines, such as the lever and pulley, to create mechanical advantage to do its work. Cranes are commonly employed in transportation for the loading and unloading of freight, in construction for the movement of materials, and in manufacturing for the assembling of heavy equipment.
A traction engine is a steam-powered tractor used to move heavy loads on roads, plough ground or to provide power at a chosen location. The name derives from the Latin tractus, meaning 'drawn', since the prime function of any traction engine is to draw a load behind it. They are sometimes called road locomotives to distinguish them from railway locomotives – that is, steam engines that run on rails.
A limited-slip differential (LSD) is a type of differential gear train that allows its two output shafts to rotate at different speeds but limits the maximum difference between the two shafts. Limited-slip differentials are often known by the generic trademark Positraction, a brand name owned by General Motors and originally used for its Chevrolet branded vehicles.
A traction motor is an electric motor used for propulsion of a vehicle, such as locomotives, electric or hydrogen vehicles, or electric multiple unit trains.
A steam shovel is a large steam-powered excavating machine designed for lifting and moving material such as rock and soil. It is the earliest type of power shovel or excavator. Steam shovels played a major role in public works in the 19th and early 20th century, being key to the construction of railroads and the Panama Canal. The development of simpler, cheaper diesel, gasoline and electric shovels caused steam shovels to fall out of favor in the 1930s.
Bulk material handling is an engineering field that is centered on the design of equipment used for the handling of dry materials. Bulk materials are those dry materials which are powdery, granular or lumpy in nature, and are stored in heaps. Examples of bulk materials are minerals, ores, coal, cereals, woodchips, sand, gravel, clay, cement, ash, salt, chemicals, grain, sugar, flour and stone in loose bulk form. It can also relate to the handling of mixed wastes. Bulk material handling is an essential part of all industries that process bulk ingredients, including: food, beverage, confectionery, pet food, animal feed, tobacco, chemical, agricultural, polymer, plastic, rubber, ceramic, electronics, metals, minerals, paint, paper, textiles and more.
A stockpile is a pile or storage location for bulk materials, forming part of the bulk material handling process.
A bucket-wheel excavator (BWE) is a large heavy equipment machine used in surface mining.
A coal preparation plant is a facility that washes coal of soil and rock, crushes it into graded sized chunks (sorting), stockpiles grades preparing it for transport to market, and more often than not, also loads coal into rail cars, barges, or ships.
A bulk-handlingcrane is one that, instead of a simple hook that can handle a range of slung loads, has an integral grab for lifting bulk cargoes such as coal, mineral ore etc.
Joy Global Inc. was a company that manufactured and serviced heavy equipment used in the extraction and haulage of coal and minerals in both underground and surface mining. The company had manufacturing facilities in Alabama, Pennsylvania, Texas, Wisconsin, Australia, Canada, China, France, South Africa, Poland and the United Kingdom. In 2017, Joy Global was acquired by Komatsu Limited and was renamed Komatsu Mining Corp.
Elecon Engineering Company Limited is an Indian multinational company headquartered in Anand, Gujarat. The company specializes in the manufacturing of industrial gear and material handling equipment. Elecon is one of the largest Asian manufacturers of industrial gears and material handling equipment for core major sector like power, steel, cement, sugar, paper, mining, rubber and many more. Elecon group has subsidiaries such as Eimco Elecon Ltd, Elecon Hydraulics, Elecon Information Technology Ltd (EITL) and Tech Elecon Pvt. Ltd. (TEPL).
Spreaders in mining are heavy equipment used in surface mining and mechanical engineering/civil engineering. The primary function of a spreader is to act as a continuous spreading machine in large-scale open pit mining operations.
A bucket chain excavator (BCE) is a piece of heavy equipment used in surface mining and dredging. BCEs use buckets on a revolving chain to remove large quantities of material. They are similar to bucket-wheel excavators and trenchers. Bucket chain excavators remove material from below their plane of movement, which is useful if the pit floor is unstable or underwater.
Coal blending is the process of mixing coals after coal has been mined to achieve quality attributes that are desirable for the coal’s intended application. The quality attributes that are most important in blending will differ from one mine site to another and also depend on how the coal seams vary in quality and their final intended use. In thermal coals, quality attributes of interest often include ash, volatile matter, total Sulfur, and gross calorific value. For coking coals, additional attributes are sometimes considered including crucible swelling number, fluidity, and RoMax.
The Diamond T 4-ton 6×6 truck was a heavy tactical truck built for the United States Army during World War II. Its G-number was G-509. Cargo models were designed to transport a 4-ton (3,600 kg) load over all terrain in all weather. There were also wrecker, dump, and other models. They were replaced by the M39 series 5-ton 6×6 trucks in the 1950s.
Dispatch & Garlick Ltd is a mechanical engineering company specialising in dairy, water and wastewater systems in Greymouth, New Zealand.