Showing posts about "mine"
Seeing from the international market, construction machinery industry has a broad market prospect. However, we should also see the cost of labor to bring the price of China's comparative advantage is the low-end products with a strong engineering machinery an important factor in competitiveness, with the deepening of economic development mode shift, this will be difficult to sustain a competitive advantage; also for this reason, high-end products and accelerate the integration of the engineering machinery industry will be the future development of the two main line, which is the construction machinery enterprises in the competition, new opportunities to achieve leapfrog development.
As the major industry of national economy, the mining machinery has played a major role in our country’s development in economy and social area. Applied in deep-processing and constructive exploration area, the mining equipments have continuously provided quantities of infrastructure industry products and energy for all walks of life , which has greatly promoted the rapid development of our national economy. For all above these, the mining equipment manufacturer has played as the basement of our country’s independent industrial system , which has also become a key signal to the balance of one country’s industrial strength.
As a key component of mining machinery, the crushing & grinding equipments include various crushing equipments like jaw crusher and other grinding equipments like Raymond mill, super thin micro grinding mill and super-huge grinding mill .The grinding and crushing equipments have not only found their extensive application in the material fine-processing field of mine, electricity, chemic, construction but also provide equipments with high-efficient and reliable technical backup for the construction of railway, roadway, hydropower ,municipal project and so on. To give a intensive research to the current development of mining equipments in the global market and particular in the advanced technology of crushing and grinding equipments ,we mining manufacturers will definitely provide more quality and high-efficient equipments with world level for our country’s coal, metal and non-metal mining development, which will play an significant role in the need of national economic development of energy and materials . Raymond mill:http://www.hx-china.com/13.html
To the 2012 development trend in mining equipment ,Henan Hxjq Machinery Group shows that world mining machinery will experience the most rapid growing in 2011.And to China mining machinery manufacturer ,the development opportunity is very valuable .And our enterprises must rapid the independent research and innovation pace and set up a comprehensive after-sales service network .Meanwhile, we should proceed the market trend to organize production , optimize product structure ,explore market, balance the ends to seek more fast and better development, which have become the major challenge in China domestic mining market. And we mining machineries should see the present development opportunity to continuously improve the technical service level to solid the market share and also strengthen the research .We mining markets will challenge the technical innovation wave with high enthusiastic.
he mining machinery in 2010 will surely be competitive .And only with the high development prospective and first-class research team and technical service man, the enterprises can stand out in the competitive market.
Some ores occur in nature as mixtures of discrete mineral particles, such as gold in gravel beds and streams and diamonds in mines. These mixtures require little or no crushing, since the valuables are recoverable using other techniques (breaking up placer material in log washers, for instance). Most ores, however, are made up of hard, tough rock masses that must be crushed before the valuable minerals can be released.
In this process stage, the crushed material can be further disintegrated in a cylinder mill, which is a cylindrical container built to varying length-to-diameter ratios, mounted with the axis substantially horizontal, and partially filled with grinding bodies (e.g., flint stones, iron or steel balls) that are caused to tumble, under the influence of gravity, by revolving the container.
A special development is the autogenous or semiautogenous mill. Autogenous mills operate without grinding bodies; instead, the coarser part of the ore simply grinds itself and the smaller fractions. Tosemiautogenous mills (which have become widespread), 5 to 10 percent grinding bodies (usually metal spheres) are added.
Concentration involves the separation of valuable minerals from the other raw materials received from the grinding mill. In large-scale operations this is accomplished by taking advantage of the different properties of the minerals to be separated. These properties can be colour (optical sorting), density (gravity separation), magnetic or electric (magnetic and electrostatic separation), and physicochemical (flotation separation).
This process is used for the concentration of particles that have sufficiently different colours (the best contrast being black and white) to be detected by the naked eye. In addition, electro-optic detectors collect data on the responses of minerals when exposed to infrared, visible, and ultraviolet light. The same principle, only using gamma radiation, is called radiometric separation.
Gravity methods use the difference in the density of minerals as the concentrating agent.
In heavy-media separation (also called sink-and-float separation), the medium used is a suspension in water of a finely ground heavy mineral (such as magnetite or arsenopyrite) or technical product (such as ferrosilicon). Such a suspension can simulate a fluid with a higher density than water. When ground ores are fed into the suspension, the gangue particles, having a lower density, tend to float and are removed as tailings, whereas the particles of valuable minerals, having higher density, sink and are also removed. The magnetite or ferrosilicon can be removed from the tailings by magnetic separation and recycled. As the professional manufacturer of complete sets of mining machinery, such as classifier, Henan Hongxing is always doing the best in products and service. hammer crusher:http://www.hxjq-crusher.com/66.html
Flotation is the most widely used method for the concentration of fine-grained minerals. It takes advantage of the different physicochemical surface properties of minerals—in particular, their wettability, which can be a natural property or one artificially changed by chemical reagents. By altering the hydrophobic (water-repelling) or hydrophilic (water-attracting) conditions of their surfaces, mineral particles suspended in water can be induced to adhere to air bubbles passing through a flotation cell or to remain in the pulp. The air bubbles pass to the upper surface of the pulp and form a froth, which, together with the attached hydrophobic minerals, can be removed. The tailings, containing the hydrophilic minerals, can be removed from the bottom of the cell.
Flotation makes possible the processing of complex intergrown ores containing copper, lead, zinc, and pyrite into separate concentrates and tailings—an impossible task with gravity, magnetic, or electric separation methods. In the past, these metals were recoverable only with expensive metallurgical processes.
Magnetic separation is based on the differing degrees of attraction exerted on various minerals bymagnetic fields. Success requires that the feed particles fall within a special size spectrum (0.1 to 1 millimetre). With good results, strongly magnetic minerals such as magnetite, franklinite, and pyrrhotite can be removed from gangue minerals by low-intensity magnetic separators. High-intensity devices can separate oxide iron ores such as limonite and siderite as well as iron-bearing manganese, titanium, and tungsten ores and iron-bearing silicates.
The electrostatic method separates particles of different electrical charges and, when possible, of different sizes. When particles of different polarity are brought into an electrical field, they follow different motion trajectories and can be caught separately. Electrostatic separation is used in all plants that process heavy mineral sands bearing zircon, rutile, and monazite. In addition, the cleaning of special iron ore and cassiterite concentrates as well as the separation of cassiterite-scheelite ores are conducted by electrostatic methods.
Mineral processing refers to a number of interrelated procedures that are all aimed at extracting valuable material from ores. Many valuable minerals are mined as ores, which are rocks that contain useful substances. Mineral processing was done by hand in the past, though in modern times it is typically achieved through the use of heavy machinery. There are four main types of mineral processing, each of which uses a different method to separate valuable materials from ore gangue. The four different methods involve the reduction of ore particle sizes, the separation of particles by size, concentration of wanted minerals, and the removal of liquids from the solid minerals.
In broader terms, mineral processing consists of two functions. Firstly, it involves the preparation and liberation, of the valuable minerals from waste minerals and secondly, the separation of these values into two or more products, called concentrates. The term separation in this case is synonymous with concentration. These functions are carried out within the constraints of the following three rules.
1. The first rule deals with the conservation of mass. The total flow of the material into the process plant equals the total flow out.
2. The second rule relates to the quality or grade of the concentrate product. In practice, it is impossible to produce a concentrate consisting of only one mineral. As the professional manufacturer of complete sets of mining machinery, such as belt conveyor, Henan Hongxing is always doing the best in products and service. raymond mill:http://www.hx-crushers.com/p54.html
3. The third rule is a corollary of the second. It is impractical to recover all of the valuable minerals into the concentrate.
In order to separate the minerals from gangue (the waste minerals), it is necessary to crush and grind the rock to unlock, or liberate, valuable minerals so that they are partially or fully exposed. This process of size reduction is called comminution. The crushing and grinding process will produce a range of particles with varying degrees of liberation (Figure 2). Any particles that exceed a target size required for physical separation or chemical extraction are returned to the crushing or the grinding circuit.
The comminution process actually begins during the mining stage through the use explosives, excavators or scrapers for softer material. This is necessary in order to generate a material that is transportable by haul trucks or conveyors. Comminution in the mineral processing plant is carried out in a sequential manner using crushers and screens followed by grinding mills and classifiers. The various types of comminution equipment including their general application are described in detail below.
In recent years, coal mine is mainly employed to make general building materials, high-grade building ceramic tiles, coating materials and fillings, high value-added products, and stuffing in road building. The ceramic tile has been one of building's decorate materials since a long time. Kaolin minerals are raw material of ceramic tile. According to statistics, output of our country ceramic tile achieves 171.5 million square meters, account for 2/5 of world's output in 2002 year. With developing science technology improving and administer level advancing, quality and variety of our country ceramic tile has very changed.
But clay raw material of ceramic tile increase losing of cultivated land, we must look for new raw material of ceramic tile as quickly as possible.
Owing to compare to clay, raw material of kaolin minerals-high-aluminum-coal mine possess higher hardness, therefore, traditional crushing techniques will bring about consuming more energy and rising cost of tile. The microwave technology can reduce crushing strength of coal mine, milling expenditure, economy energy, reducing cost. This paper indicates that traditional milling technics need 4.00 hours when coal mine is milled to 325 without microwave radiation. The milling only needs 55.00 minute after microwave radiation 5.00 minute. So, microwave radiation pre-crushing coal mine raw material can save 1/2 of electrical fee in actual project per year. As the professional manufacturer of complete sets of mining machinery, such as spiral separator, Henan Hongxing is always doing the best in products and service. jaw crusher:http://www.hxjq-crusher.com/
Under the situation of lacking energy, mining machinery equipment manufactory is paying more attention on high efficiency and energy saving. Henan Hongxing Machinery takes notice on update and promotion of mining machinery equipment, and its HGM series medium-speed micro-powder making machine is the new generation equipment. The HGM series grinder is one kind of fine powder and superfine powder processing machine, and is used for coal mine, marble, chalk, barite, bentonite, rock phosphate, rectorite etc. It has many advantages: high efficiency, long life of quick-wear part, high safety and reliability, super fine powder, environmental protection and so on. The whole equipment of HGM medium-speed grinder consists of hammer crusher, bucket elevator, storage bin, electric magnetic feeder, powder collector, pulse dust removal, main engine, powder concentrator, high pressure fan, silencer.
Henan Hongxing Machinery is the professional manufacturer of powder making machines. Through 20 years of researches and development, there are a series of powder making machines, HGM series micro-powder grinder, MTW series Europen trapezium grinder, LM series vertical grinder, super pressure trapezium grinder, high pressure roll grinder.
A coal miner can perform a number of tasks around a coal mine, depending on the type of mine where he or she works. Despite significant safety improvements, coal mining continues to be an extremely dangerous occupation, and no matter what kind of work a coal miner does, it's necessary to be physically fit in addition to being attentive and cautious. Being aware of the surroundings in a mine can save lives, making alertness an important part of the job description for miners.
In surface mining operations, a coal miner can operate the heavy equipment which is used to strip away the topsoil from a seam of coal, drill holes in the coal for the placement of explosives, or work as a blaster, setting explosive charges to break up coal seams so that they can be removed. Other coal miners in surface operations work with the equipment which is used to remove the coal loosened by blasting operations. Coal miners usually train to do this work on the job, although some mining companies offer classroom training opportunities as well as practice opportunities in a non-working mine so that miners can get comfortable with the work.
When a company needs to mine underground to access coal, a coal miner can be part of the crew which lays out the mine and provides reinforcement and support to prevent collapses. He or she can also work on the teams which actually break up and remove the coal, using heavy equipment rather than the iconic shovels many people associate with coal mining. Coal miners can also work as safety inspectors, making sure that conditions in the mine are safe and addressing safety concerns as they arise. As the professional manufacturer of complete sets of mining machinery, such as cone crusher, Henan Hongxing is always doing the best in products and service. ore beneficiation：http://www.hx-crushers.com/p58.html
A skilled coal miner can work as a supervisor, overseeing work by other employees. Working as a supervisor can be less dangerous because supervisors are not necessarily in the thick of the work, but it also comes with major responsibilities, as supervisors must look out for the safety of the employees who work for them.
Coal mining is very dirty work, and it exposes people to a number of risks. Inhaled coal dust can cause lung problems, for example, and miners can be injured by heavy equipment, vehicle collisions, explosions, gas leaks, and collapses. Many coal miners are unionized so that they can enjoy more protections as workers and so that they can access assistance from the union if they are injured and need medical, legal, or financial help.