Coal: The Black Treasure
Definition Coal is a combustible black or brownish-black sedimentary rock, primarily composed of carbon along with hydrogen, oxygen, nitrogen, and sulfur, typically formed alongside earthy impurities underground.
History Humans have been using coal as a fuel source since ancient times. With the advent of the Industrial Revolution, coal consumption surged, becoming a primary energy source.
Applications
大地矿产资源有限公 司
Coal
Export
Domestic
PT.HARTA BUMI RESOURCES
Exclusive
COAL TRADING
Our coal trading business commenced in October 2010, spearheaded by a team of experienced personnel owning strong local expertise and well-developed relationships across the coal value chain from the ground up to the end-buyer.
We source our thermal coal directly from a selected number of Indonesia’s largest and most well-established coal producers. We serve coal users in Asia operating across various industries, with a primary focus on China, which is the world’s largest importer of thermal coal. Our excellent reliability and service quality has enabled us to establish a strong customer base.
We operate mainly on FOB basis and our current monthly trading volume is approximately 50,000-100,000 metric tonnes.
Coal Mining
Coal Mining
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ASTM
ASTM - American Society for Testing and Materials
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GAR - Gross As Received
GAR - Gross As Received. Thermal coal is quoted on a GAR basis, except for Europe/ARA, Richards Bay 6,000 kcal/kg, and Japan and Korea West CIF, which are quoted on a NAR (Net As Received) basis.
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Fixed carbon
Fixed carbon - Fixed carbon is the solid combustible residue that remains in the furnace after volatile matter is distilled off, comprised mostly of carbon but also containing some hydrogen, oxygen, sulphur and nitrogen not driven off with the gases. It provides a rough estimate of the heating value of coal.
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HGI
HGI - The relative ease with which coal can be pulverised depends on the strength of the coal and is measured by the Hardgrove Grindability Index (HGI). This empirical test indicates how difficult it would be to grind a specific coal to the particle size necessary for effective combustion in a pulverized coal fired boiler
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COAL SPECIFICATIONS
We exclusively trade thermal coal of Indonesian origin and offer three main calorific values – GAR 4200 kcal/kg, NAR 4700 kcal/kg and NAR 5500 kcal/kg. The table below indicates the typical specifications of each category of coal under the American Society for Testing and Materials Standard.
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GLOSSARY
ADB - Air-Dried Basis. In coal sample analysis, ADB neglects the presence of moistures other than inherent moisture while DB (dry-basis) leaves out all moistures, including surface moisture, inherent moisture, and other moistures.
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ARB - As-Received Basis.
ARB - As-Received Basis. In coal sample analysis, ARB puts all variables into consideration and uses the total weight as the basis of measurement. ARB is the most widely used basis in industrial applications.
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Ash content
Ash content - Ash content is the non-combustible residue that remains after coal is burnt. Ash reduces handling and burning capacity, affects combustion efficiency and boiler efficiency and therefore increases handling costs.
Coal Mining
Coal Mining
Coal Mining
Coal Mining
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Inherent moisture
Inherent moisture > Inherent moisture (or bed moisture) means moisture that exists as an integral part of the coal seam in its natural state, including water in pores, but excluding that present in macroscopically visible fractures.
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Sulphur
Sulphur > Sulphur content in coal presents problems with utilization and resultant pollution, as it causes corrosion and fouling of boiler tubes, and atmospheric pollution when released in flue gases.
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Total moisture
Total moisture > Total moisture in coal is represented by measuring weight loss from aggressive drying in an air atmosphere under rigidly controlled conditions of temperature, time and air flow. The presence of moisture is an important factor in both the storage and the utilization of coal, as it adds unnecessary weight during transportation, reduces the calorific value, and poses some handling problems.
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Volatile matter
Volatile matter > Volatile matter is the material that is driven off when coal is heated to 950 °C in the absence of air under specified conditions. It consists of a mixture of gases, low-boiling-point organic compounds that condense into oils upon cooling, and tars. In general, coals with high volatile-matter content ignite easily and are highly reactive in combustion applications.