coal and methane

Coal Bed Methane

Methane recovery from un-mined coal seams is often referred to as Coal Bed Methane extraction (CBM). This includes the recovery of methane prior to mining taking place. Virgin Coal Bed Methane (VCBM) describes the recovery of methane from seams in which the coal will remain unmined.

Coal Bed Methane is recovered from un-mined coal seams for two primary reasons:

• It may be necessary to drain the seam of as much methane as possible before mining takes place. This reduces the risk of explosion and mitigates methane emissions to the atmosphere once the process of extracting the coal begins.
• The methane may be recovered for its energy production potential, regardless of whether the coal will actually be extracted.

The potential for future mining operations is largely dependent on the accessibility of the coal seams. Coal found at extremely deep depths is often not considered feasible for extraction because of practical, safety and economic considerations. In such cases, methane recovery activity is purely for the purpose of energy generation and does not have safety or climate change benefits (as the methane would not have been emitted).

Coal Bed Methane Extraction / Recovery Techniques

Methane from unmined coal seams is recovered through drainage systems constructed by drilling a series of vertical or horizontal wells directly into the seam. Water must first be drawn from the coal seam in order to reduce pressure and release the methane from its adsorbed state on the surface of the coal and the surrounding rock strata. Once dewatering has taken place and the pressure has been reduced, the released methane can escape more easily to the surface via the wells.
The choice of vertical or horizontal wells is dependent on the geology of the coal seam. In the case of seams at shallow depths, vertical wells have been traditionally used. These vertical systems often use layers of fracture wells, which drain the methane from fractures in the coal seam produced as result of the increased pressure created during the dewatering process. At these shallow depths, the combination of high permeability and low pressure make the vertical systems ideal as extra methane flow enhancement is not required and the structure of the vertical and fracture wells remains stable.
At greater depths, the structure of the vertical and fracture wells may not be able to withstand the higher pressure levels and extra flow enhancement may be required to produce the methane. This is often true in cases of VCBM recovery due to the depths at which the coal is found. In these instances, horizontal drilling techniques may be used for increased accuracy and flexibility. Within these horizontal systems, flow enhancement techniques such as extra hydraulic fracturing - where water is pumped into the seam at high pressure - may be deployed to further facilitate the release of the methane from coals seams.
Although horizontal systems can recover much higher volumes of methane from coal seams at extreme depths than a vertical system possibly could, recovery efficiency is relatively low and heavily dependent on the overall length of the drill through the coal seam. Horizontal systems are still in their infancy and over time there may be increased movement towards their use as the technologies mature and efficiencies are improved.

Utilisation

Coal Bed Methane generally provides the highest concentration of methane recoverable from coal seams due to the lack of exposure to air from mining. Concentration levels of methane recovered via these techniques can often exceed 95%, making the gas suitable for use as a direct replacement for conventional natural gas in pipeline networks. This gas can then be pumped directly to homes and businesses for use in cooking and heating.
Natural gas pipeline networks need to be easily accessible for the addition of the coal seam methane to be economic and practical. Existing pipeline networks can be extended to reach CBM projects if the distances to be covered and geographical features make the project economically feasible.
The high quality of the gas recovered from unmined coal seams also renders it suitable for replacing or supplementing conventional natural gas in power generation systems, such as gas turbines and gas engine systems. This utilisation option increases in viability the closer the generator is located to the methane recovery site.
Recovered CBM can also be stored in gas canisters for local distribution as a domestic fuel and is also storable in compressed liquid form for utilisation as vehicle fuel.

Global Resource Base & Potential for Utilisation

The largest CBM resource bases lie in the former Soviet Union, Canada, China, Australia and the United States. However, much of the world’s CBM recovery potential remains untapped. In 2006 it was estimated that of global resources totalling 143 trillion cubic metres, only 1 trillion cubic metres was actually recovered from reserves. This is due to a lack of incentive in some countries to fully exploit the resource base, particularly in parts of the former Soviet Union where conventional natural gas is abundant.

Country	Estimated CBM Resource Base (trillion cubic metres)
Canada	17 to 92
Russia	17 to 80
China	30 to 35
Australia	8 to 14
USA	4 to 11

Source: IEA CCC 2005
The United States has demonstrated a strong drive to utilise its resource base. Exploitation in Canada has been somewhat slower than in the US, but is expected to increase with the development of new exploration and extraction technologies.
The potential for supplementing significant proportions of natural gas supply with CBM is also growing in China, where demand for natural gas is set to outstrip domestic production by 2010 and CBM offers an alternative supply.

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coal methane

Coal Mine Methane

The methane recovered from working mines can be grouped under the term Coal Mine Methane (CMM). Two key drivers for CMM recovery are mine safety and the opportunity to mitigate significant volumes of methane emissions arising from coal mining activities. There is also strong potential to utilise CMM for energy production.

Methane emissions in working mines arise at two key stages:
(1) Methane is released as a direct result of the physical process of coal extraction. In many modern underground mines, the coal is extracted through longwall mining. Longwall mining, as with other sub-surface techniques, releases methane previously trapped within the coal seam into the air supply of the mine as layers of the coal face are removed, thus creating a potential safety hazard.
(2) Methane emissions arise from the collapse of the surrounding rock strata after a section of the coal seam has been mined and the artificial roof and wall supports are removed as mining progresses to another section. The debris resulting from the collapse is known as gob and also releases methane or ‘gob gas’ into the mine.

Recovery Techniques

Recovery techniques for CMM vary for each of the two stages of emissions.
(1) Methane released from the worked coal face can be diluted and removed by large ventilation systems designed to move vast quantities of air through the mine. These systems dilute methane within the mine to concentrations below the explosive range of 5-15%, with a target for methane concentrations under 1%. The ventilation systems move the diluted methane out of the working areas of the mine into shafts leading to the surface. The methane removed from working mines via this technique is known as Ventilation Air Methane (VAM).
The VAM is released through the ventilation shafts and can then be destroyed or captured for utilisation rather than allowing it to be released directly into the atmosphere, as may have occurred in the past. VAM has the lowest concentration levels of all forms of recoverable methane from coal seams because of its high exposure to air; often displaying levels of 0.05-0.8%.
(2) To pre-empt the release of gob gas from post mining collapse, it is possible for vertical gob wells to be drilled directly into the coal seam’s surrounding strata before mining activities pass through that section. These pre-drilled wells can then remove the gob gas once the collapse takes place, thus avoiding the release of methane directly into the mine. The gob gas can then be destroyed or captured for utilisation via the wells, rather than allowing it to be released directly into the atmosphere. As gob gas is exposed to significantly lower volumes of air than VAM, it displays much higher methane concentration levels - typically between 35-75%.

Destruction & Utilisation

There are two main options available for the end utilisation of CMM.
(1) Power Generation - If projects are seeking to take advantage of the benefits that CMM can provide as an energy source, there are alternatives to simply destroying the gas through flaring systems. Although both VAM and gob gas provide much lower methane concentrations than methane recovered from unmined coal seams, there are power generation technologies available today that can harness the energy production potential of these resources. VAM can not only be used for combustion dilution and cooling purposes in standard gas turbines, but also as a primary fuel in a number of ‘lean-burn’ gas turbine systems. These systems can utilise VAM with methane concentrations as low as 1% (hence the term lean-burn) and therefore can harness the energy potential of high percentages of the VAM recovered from working mines.
VAM’s potential as an energy source can also be harnessed by a number of oxidation systems available on the market today. Methane can be converted to CO₂ by the process of oxidation, thus reducing its global warming potential. This process also creates energy which can be used to generate heat or power. Oxidation systems can utilise VAM with methane concentration levels of less than 1%. These systems are often deployed on-site to provide auxiliary heat and power to the mine.
(2) Flaring - Options exist for destroying gas that would otherwise be released directly into the atmosphere. Flaring is an important technology for disposing of the methane safely and efficiently and can help to significantly reduce a major source of GHG emissions. The flared methane is converted to CO₂, heat and water. Although flaring still leads to GHG emissions in the form of CO₂, because methane’s global warming potential is 23 times greater than that of CO₂, flaring actually reduces the overall greenhouse effect. However, the resulting CO₂ emissions still clearly present a huge challenge in terms of combating global warming and flaring is therefore not regarded as the most efficient or environmentally friendly of end use options.
Flaring can be performed in either open or enclosed systems, and the technique is similar to that deployed in the oil and gas industries. This method of methane disposal is relatively cheap when compared to the extra costs incurred in developing power generation infrastructure or incorporating recovered methane into a region’s natural gas pipeline network.

Coal Mine Methane Potential

Methane emissions from working underground mines make up the majority of emissions from coal mining related activities - around 90% in 2006 according to figures from the US Environmental Protection Agency (US EPA). VAM is widely found to make the greatest contribution to these emissions, with US EPA figures suggesting that over 50% of all global methane emissions from coal mining arise in this form.
At present, there are more than 220 CMM projects worldwide in 14 countries. These projects help to avoid around 3.8 billion cubic metres of methane emissions every year.
Australia has been particularly active in deploying the power generation and oxidation systems currently available. The United States also has vast potential for utilising CMM for energy purposes, but continues to primarily incorporate the gas directly into its pipeline network rather than deploy power generation systems specifically designed for CMM.
Outside of the developed world, China is experiencing significant growth in interest in the recovery and utilisation of CMM due to its high volume of methane emissions from coal mining and the particularly gassy coal seams that are found in the country. A number of projects utilising CMM for energy purposes in China are currently approved or awaiting approval under the Kyoto Protocol’s Clean Development Mechanism (CDM). Of these projects, a number plan to utilise CMM as a fuel within power generation systems. The greatest potential for CMM projects in the developing world lies under the CDM due to the increased profitability that the generation of emissions reduction credits can provide, which acts as an economic driver.
The potential for the development of CMM projects is also high in a number of other countries, including India and Mexico. Mexico in particular is a key area for potential development as some of the world’s gassiest mines are located there.

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coal and gas

Methane (CH₄) is a gas formed as part of the process of coal formation – coalification. When coal is mined methane is released from the coal seam and the surrounding disturbed rock strata. Methane can also be released as a result of natural erosion or faulting.

The methane content in coal seams generally increases the deeper the seam, and also with age. As the depth of the coal seam increases, so does the pressure level. This in turn reduces the level of permeability, causing the methane to be much more tightly bound to the coal and surrounding rock strata. Underground mining can therefore produce substantially greater levels of methane than surface mining. In fact, underground mines account for the overwhelming majority (up to 90%) of all methane emissions from the coal sector.

Depth Interval (metres)	Mean methane content (cubic metres per tonne of coal)
100	0.02
500	0.99
1000	3.73
1500	4.89
2000	7.09

Source: IEA CCC 2005
Methane is highly combustible – its release can have serious implications for the safety of mine operations. It is also a potent greenhouse gas (GHG) – 23 times more harmful than carbon dioxide (CO₂).
Tackling methane emissions is therefore an important step in meeting the challenge of climate change and in ensuring the safety of mining operations. Methane can also act as a valuable source of energy- it is the principal constituent of natural gas - allowing countries to further diversify their energy supplies.

Why Recover Methane from Coal Seams?

There are three main drivers for the recovery of methane from coal seams.
(1) Safety
Methane is released during the process of extracting coal in both surface and underground mining. The released methane then mixes with air, which becomes highly explosive if methane concentration levels reach 5-15%. Methane explosions are devastating, causing significant loss of life and damage to property. There is significant industry effort to prevent these accidents occurring.
The risk of explosion is a particular problem in underground mines, where providing a sufficient level of ventilation air is essential. Failure to provide enough air to dilute the methane below the 5-15% range can put miners at risk due to the threat of explosion. In surface mining, the released methane is heavily diluted by its immediate exposure to air and therefore the risk of explosion is minimal.
Methane explosions in underground mines cause a large number of deaths around the world each year. While these numbers are still too high, they have been falling year on year in recent times as awareness of the hazards of methane has increased and methane recovery technologies have been improved and deployed on a wider scale.
(2) Reducing Greenhouse Gas Emissions
The recovery of methane released during coal mining plays an important role in global efforts to reduce GHG emissions and mitigate climate change. Methane is one of five greenhouse gases covered by the Kyoto Protocol and this provides opportunities for countries to meet their obligations under Kyoto by undertaking projects that reduce methane emissions from coal mining activities. These projects can be developed domestically or in host countries under the Protocol’s Clean Development Mechanism (CDM) and Joint Implementation (JI) scheme.
The global warming potential (GWP) of methane is 23 times greater than that of CO₂, which means that for a given volume of methane emitted, the resulting global warming effect will be 23 times stronger over one hundred years compared to the same volume of CO₂. Methane remains in the atmosphere for a period of approximately 12 years after it has been emitted. In comparison, CO₂ is estimated to have an atmospheric lifetime of 50-200 years.
The differences in the GWP and atmospheric lifetimes of methane and CO₂ means that methane has a relatively large global warming effect over a short period of time, whereas CO₂ has a relatively small global warming effect but over a much longer period of time.
Coal mining is an important anthropogenic source of methane emissions. Although agriculture accounts for by far the largest proportion of methane emissions from human activities, emissions from all coal mining related activities - extraction, transport and storage - accounted for around 8% of total global anthropogenic methane emissions in 2006.

Global Methane Emissions from Human Activities (2006)

Source: M2M 2006

(3) Energy Generation
Methane is a valuable energy resource; 70-90% of natural gas is methane (with the rest being made up of ethane, propane, butanes, pentanes and higher molecular weight hydrocarbons, elemental sulphur, and sometimes helium and nitrogen). Coal seam methane therefore provides a useful ‘unconventional’ source of natural gas.
Coal seam gas resources are distributed differently to the ‘conventional’ natural gas found in natural gas fields. This allows countries with restricted access to natural gas but plentiful coal supplies to utilise alternative sources of natural gas.
Coal seam gas of a high quality (typically with a concentration level of over 93%) can be fed into the existing gas pipeline network to supplement or replace conventional natural gas. The United States has been utilising vast quantities of coal seam methane in its natural gas supply since the early 1990s. This can be supplied directly to homes and businesses for use in cooking and heating. Coal seam gas can also be utilised to replace or supplement conventional natural gas in electricity generation systems such as gas turbines and gas engine systems. These systems are often deployed directly on mine sites to provide auxiliary power to the mines themselves.

How is Coal Seam Methane recovered?

A range of technologies are available to recover methane from coal and these can be broken down into three categories.
(1) Coal Bed Methane (CBM)
Methane recovered from un-mined coal seams. The coal seams may be mined in the future but this is largely dependent upon geological factors such as coal depth and quality. 
(2) Coal Mine Methane (CMM)
Methane recovered during mining activities as the coal is in the process of being extracted and thus emitting significant quantities of the gas.
(3) Abandoned Mine Methane (AMM)
Methane recovered from mines that have been abandoned following the completion of mining operations. Significant amounts of methane may remain trapped in the mine or may continue to be emitted from openings.

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Underground Coal Gasification

Underground Coal Gasification (UCG) is a method of converting unworked coal - coal still in the ground - into a combustible gas which can be used for industrial heating, power generation or the manufacture of hydrogen, synthetic natural gas or diesel fuel.

UCG technology allows countries that are endowed with coal to fully utilise their resource from otherwise unrecoverable coal deposits in an economically viable and environmentally safe way. UCG turns this resource into high value products:

• clean power
• liquid fuels
• syngas
• fertilisers and other chemical feedstocks.

UCG uses a similar process to surface gasification. The main difference between both gasification processes is that in UCG the cavity itself becomes the reactor so that the gasification of coal takes place underground instead of at the surface.

UCG Process

The basic UCG process involves drilling two wells into the coal, one for injection of the oxidants (water/air or water/oxygen mixtures) and another well some distance away to bring the product gas to the surface.
The coal at the base of the first well is then heated to temperatures that would normally cause the coal to burn. However, through careful regulation of the oxidant flow, the coal does not burn but rather separates into the syngas. The syngas is then drawn out of the second well. Two different methods of UCG have evolved and are commercially available:

• Vertical wells combined with methods for opening the pathway between the wells.
• Inseam boreholes using technology adapted from oil and gas production that can move the injection point during the process

Tests in Europe in the late 1990s demonstrated it was possible to have greater control of deep drilling, to create larger cavities in the coal seam for the gases, and to provide more efficient combustion. In addition, while the process had previously been criticised for generating large quantities of hydrogen as a useless by-product, hydrogen is now in demand as a feedstock for the chemical industry and shows potential as an alternative fuel for vehicles.
The advantages in the use of this technology - especially in the emerging markets of China, India and South Africa - are the low plant costs (as no surface gasifiers are required) and the absence of coal transport costs.
UCG also presents the opportunity to reduce emissions as there are fewer surface emissions. UCG technology could also have synergies with CCS as the CO₂ could be stored in the coal cavity after gasification.

Developments, Projects & Interest

In the last few years there has been significant renewed interest in UCG as the technology has moved forward considerably.

• China has about 30 projects in different phases of preparation that use underground coal gasification.
• India plans to use underground gasification to access an estimated 350 billion tonnes of coal. In 2007 India compiled a 93-page status report on underground coal gasification that highlighted interest from many of the country's biggest companies.
• South African companies Sasol and Eskom both have UCG pilot facilities that have been operating for some time, giving valuable information and data.
• In Australia, Linc Energy has the Chinchilla site, which first started operating in 2000. Carbon Energy has completed a successful 100 day commercial scale study in Bloodwood Creek in 2008.

Demonstration projects and studies are also currently under way in a number of countries, including the USA, Western and Eastern Europe, Japan, Indonesia, Vietnam, India, Australia and China, with work being carried out by both industry and research establishments.
A number of issues remain to be resolved before wider deployment can be achieved.

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Coal to Liquids

Converting coal to a liquid fuel (CTL) – a process referred to as coal liquefaction – allows coal to be utilised as an alternative to oil. There are two different methods for converting coal into liquid fuels:

• Direct liquefaction works by dissolving the coal in a solvent at high temperature and pressure. This process is highly efficient, but the liquid products require further refining to achieve high grade fuel characteristics.
• Indirect liquefaction gasifies the coal to form a ‘syngas’ (a mixture of hydrogen and carbon monoxide). The syngas is then condensed over a catalyst – the ‘Fischer-Tropsch’ process – to produce high quality, ultra-clean products.

An array of products can be made via these processes – ultra-clean petroleum and diesel, as well as synthetic waxes, lubricants, chemical feedstocks and alternative liquid fuels such as methanol and dimethyl ether (DME).

Where is it Used?

South Africa has been producing coal-derived fuels since 1955 and has the only commercial coal to liquids industry in operation today. Not only are CTL fuels used in cars and other vehicles, South African energy company Sasol’s CTL fuels also have approval to be utilised in commercial jets. Currently around 30% of the country’s gasoline and diesel needs are produced from indigenous coal. The total capacity of the South African CTL operations now stands in excess of 160,000bbl/d.
CTL is particularly suited to countries that rely heavily on oil imports and that have large domestic reserves of coal. There are a number of CTL projects around the world at various stages of development. Liquid fuels from coal can be delivered from an existing pump at a filling station via existing distribution infrastructure and used, without modification, in the current vehicle fleet.

CTL Outside of Transportation

Fuels produced from coal also have potential outside the transportation sector. In many developing countries, health impacts and local air quality concerns have driven calls for the use of clean cooking fuels. Replacing traditional biomass or solid fuels with liquefied petroleum gas (LPG) has been the focus of international aid programmes. LPG however, is an oil derivative – and is thus affected by the expense and price volatility of crude oil. Coal-derived dimethyl ether (DME) is receiving particular attention today as it is a product that holds out great promise as a domestic fuel. DME is non-carcinogenic and non-toxic to handle and generates less carbon monoxide and hydrocarbon air pollution than LPG. DME can also be used as an alternative to diesel for transport, as well as for on and off-grid power applications.

Benefits of CTL

Coal to liquids has a number of benefits:

• Coal is affordable and available worldwide enabling countries to access domestic coal reserves – and a well-supplied international market - and decrease reliance on oil imports, improving energy security.
• Coal liquids can be used for transport, cooking, stationary power generation, and in the chemicals industry.
• Coal-derived fuels are sulphur-free, low in particulates, and low in nitrogen oxides.
• Liquid fuels from coal provide ultra-clean cooking fuels, alleviating health risks from indoor air pollution

Increasing energy demand and rises in vehicle ownership means that it is important for countries to review the balance of their energy supply mix. 96% of all energy used in transport comes from petroleum; it therefore dominates the transport sector. CTL – along with gas-to-liquids (GTL) and biomass-to-liquids (BTL) - allows countries the option of diversifying the liquid fuel supplies.
Interest in constructing CTL plants tends to increase when the oil price is high and countries are concerned about the cost of their oil imports. When the oil price drops, the economics of coal to liquids plants are less favourable.

Emissions Reductions from Synthetic Fuels (Europe)

Source: Alliance for Synthetic Fuels in Europe

GHG Emissions

The conversion of any feedstock to liquid fuels is an energy intensive one. Emissions across the entire process have to be considered. While the coal to liquids process is more CO₂ intensive than conventional oil refining, there are options for preventing or mitigating emissions. For coal to liquids plants, carbon capture and storage can be a low cost method of addressing CO₂ concerns. Where co-processing of coal and biomass is undertaken, and combined with CCS, greenhouse gas emissions over the full fuel cycle may be as low as one-fifth of those from fuels provided by conventional oil.

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Coal Combustion Products

Coal combustion products (CCPs) can play an important role in concrete production. CCPs are the by-products generated from burning coal in coal-fired power plants. These by-products include:

• fly ash
• bottom ash
• boiler slag
• flue gas desulphurisation gypsum
• others types of material such as fluidised bed combustion ash, cenospheres, and scrubber residues

Fly ash can be used to replace or supplement cement in concrete. In the USA, for example, more than half of the concrete produced is blended with fly ash.
Among the most significant environmental benefits of using fly ash over conventional cement is that greenhouse gas (GHG) emissions can be significantly reduced. For every tonne of fly ash used for a tonne of portland cement (the most common type of cement in general use around the world) approximately one tonne of carbon dioxide is prevented from entering the earth’s atmosphere. Fly ash does not require the energy-intensive kilning process required by portland cement.
Using CCPs reduces GHG emissions, reduces the need for landfill space, and eliminates the need to use primary raw materials. Fly ash produces a concrete that is strong and durable, with resistance to corrosion, alkali-aggregate expansion, sulphate and other forms of chemical attack.
Coal combustion products are expected to continue to play a major role in the concrete market. Their use in other building products is also expected to grow as sustainable construction becomes more prominent, and more architects and building owners understand the benefits of using CCPs.

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Coal & Cement

The cement industry requires energy to produce cement and coal is an important source of the energy needed.

Cement is critical to the construction industry – mixed with water, and gravel it forms concrete, one of the key construction materials available today. Varying the mix of cement, sand and aggregate enables concrete to be used in a range of applications. Products can be designed, coloured and shaped to accommodate a variety of environmental conditions, architectural requirements and to withstand a wide range of loads, stresses and impacts.
Over 3.3 billion tonnes of cement were consumed globally in 2010. China's cement consumption alone reached over 1.8 billion tonnes.

What is Cement?

Cement is made from a mixture of calcium carbonate (generally in the form of limestone), silica, iron oxide and alumina. A high-temperature kiln, often fuelled by coal, heats the raw materials to a partial melt at 1450°C, transforming them chemically and physically into a substance known as clinker. This grey pebble-like material is comprised of special compounds that give cement its binding properties. Clinker is mixed with gypsum and ground to a fine powder to make cement.
Coal is used as an energy source in cement production. Large amounts of energy are required to produce cement. It takes about 200 kg of coal to produce one tonne of cement and about 300-400 kg of cement is needed to produce one cubic meter of concrete (World Business Council for Sustainable Development).
Coal combustion products (CCPs), such as Fly Ash also play an important role in cement manufacture and in the construction industry generally.

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Coal & Steel

Steel is an essential material for modern life. The manufacture of steels delivers the goods and services that our societies need – healthcare, telecommunications, improved agricultural practices, better transport networks, clean water and access to reliable and affordable energy.

Global steel production is dependent on coal. 70% of the steel produced today uses coal. Metallurgical coal – or coking coal – is a vital ingredient in the steel making process. World crude steel production was 1.4 billion tonnes in 2010. Around 721 million tonnes of coking coal was used in the production of steel.

How is Steel Produced?

Steel is an alloy of iron and carbon. Steel is produced via two main routes

• Integrated smelting involving blast furnace (BF) iron-making followed by basic oxygen furnace (BOF)
• Electric arc furnaces (EAF).

Raw Materials

Steel is an alloy based primarily on iron. As iron occurs only as iron oxides in the earth’s crust, the ores must be converted, or ‘reduced’, using carbon. The primary source of this carbon is coking coal.
Coke Making
Coking coal is converted to coke by driving off impurities to leave almost pure carbon. The physical properties of coking coal cause the coal to soften, liquefy and then resolidify into hard but porous lumps when heated in the absence of air. Coking coal must also have low sulphur and phosphorous contents. Almost all metallurgical coal is used in coke ovens.
The coking process consists of heating coking coal to around 1000-1100ºC in the absence of oxygen to drive off the volatile compounds (pyrolysis). This process results in a hard porous material - coke. Coke is produced in a coke battery which is composed of many coke ovens stacked in rows into which coal is loaded.
The coking process takes place over long periods of time between 12-36 hours in the coke ovens. Once pushed out of the vessel the hot coke is then quenched with either water or air to cool it before storage or is transferred directly to the blast furnace for use in iron making.
Iron Making
Iron ore is mined in around 50 countries – the largest producers are Australia, Brazil and China. Around 98% of iron ore is used in steel-making.
During the iron-making process, a blast furnace is fed with the iron ore, coke and small quantities of fluxes (minerals, such as limestone, which are used to collect impurities). Air which is heated to about 1200°C is blown into the furnace through nozzles in the lower section. The air causes the coke to burn, producing carbon monoxide which reacts with the iron ore, as well as heat to melt the iron. Finally, the tap hole at the bottom of the furnace is opened and molten iron and slag (impurities) are drained off.
Basic Oxygen Furnace
The most commonly applied process for steel-making is the integrated steel-making process via the Blast Furnace – Basic Oxygen Furnace.
In the basic oxygen furnace, the iron is combined with varying amounts of steel scrap (less than 30%) and small amounts of flux. A lance is introduced in the vessel and blows 99% pure oxygen causing a temperature rise to 1700°C. The scrap melts, impurities are oxidised, and the carbon content is reduced by 90%, resulting in liquid steel.
Other processes can follow – secondary steel-making processes – where the properties of steel are determined by the addition of other elements, such as boron, chromium and molybdenum, amongst others, ensuring the exact specification can be met.
Optimal operation of the blast furnace demands the highest quality of raw materials – the carbon content of coke therefore plays a crucial role in terms of its effect in the furnace and on the hot metal quality. A blast furnace fed with high quality coke requires less coke input, results in higher quality hot metal and better productivity. Overall costs may be lower, as fewer impurities in the coke mean smaller amounts of flux must be used.
Around 0.6 tonnes (600 kg) of coke produces 1 tonne (1000 kg) of steel, which means that around 770 kg of coal are used to produce 1 tonne of steel through this production route.
Basic Oxygen Furnaces currently produce about 70% of the world’s steel. A further 29% of steel is produced in Electric Arc Furnaces.
Electric Arc Furnaces
The Electric Arc Furnace process, or mini-mill, does not involve iron-making. It reuses existing steel, avoiding the need for raw materials and their processing. The furnace is charged with steel scrap, it can also include some direct reduced iron (DRI) or pig iron for chemical balance.
The EAF operates on the basis of an electrical charge between two electrodes providing the heat for the process. The power is supplied through the electrodes placed in the furnace, which produce an arc of electricity through the scrap steel (around 35 million watts), which raises the temperature to 1600˚C, melting the scrap. Any impurities may be removed through the use of fluxes and draining off slag through the taphole.
Electric Arc Furnaces do not use coal as a raw material, but many are reliant on the electricity generated by coal-fired power plant elsewhere in the grid.
Around 150 kg of coal are used to produce 1 tonne of steel in electric arc furnaces.

Pulverised Coal Injection

Pulverised Coal Injection (PCI) technology involves injecting coal directly into the blast furnace to provide the carbon for iron-making – displacing some of the coke required for the process. A wider range of coals can be used in PCI, including steam coal which has a lower carbon content than coking coal. This method has a number of advantages, including reducing overall costs and prolonging the life of existing coke batteries.

Recycling

Steel is 100% recyclable. The BOF process uses up to 30% recycled steel (scrap) and around 90-100% is used in EAF production.

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Coal & Electricity

Modern life is unimaginable without electricity. It lights houses, buildings, streets, provides domestic and industrial heat, and powers most equipment used in homes, offices and machinery in factories. Improving access to electricity worldwide is critical to alleviating poverty.

Coal plays a vital role in electricity generation worldwide. Coal-fired power plants currently fuel 41% of global electricity. In some countries, coal fuels a higher percentage of electricity.

Coal in Electricity Generation
South Africa 93%	Poland 87%	PR China 79%
Australia 78%	Kazakhstan 75%	India 68%
Israel 58%	Czech Rep 51%	Morocco 51%
Greece 54%	USA 45%	Germany 41%

Source: IEA 2012

How is Coal Converted to Electricity?

Steam coal, also known as thermal coal, is used in power stations to generate electricity.
Coal is first milled to a fine powder, which increases the surface area and allows it to burn more quickly. In these pulverised coal combustion (PCC) systems, the powdered coal is blown into the combustion chamber of a boiler where it is burnt at high temperature (see diagram below). The hot gases and heat energy produced converts water – in tubes lining the boiler – into steam.

The high pressure steam is passed into a turbine containing thousands of propeller-like blades. The steam pushes these blades causing the turbine shaft to rotate at high speed. A generator is mounted at one end of the turbine shaft and consists of carefully wound wire coils. Electricity is generated when these are rapidly rotated in a strong magnetic field. After passing through the turbine, the steam is condensed and returned to the boiler to be heated once again.
The electricity generated is transformed into the higher voltages (up to 400,000 volts) used for economic, efficient transmission via power line grids. When it nears the point of consumption, such as our homes, the electricity is transformed down to the safer 100-250 voltage systems used in the domestic market.

Efficiency Improvements

Improvements continue to be made in conventional PCC power station design and new combustion technologies are being developed. These allow more electricity to be produced from less coal - known as improving the thermal efficiency of the power station. Efficiency gains in electricity generation from coal-fired power stations will play a crucial part in reducing CO₂ emissions at a global level.
Efficiency improvements include the most cost-effective and shortest lead time actions for reducing emissions from coal-fired power generation. This is particularly the case in developing countries where existing power plant efficiencies are generally lower and coal use in electricity generation is increasing. Not only do higher efficiency coal-fired power plants emit less carbon dioxide per megawatt (MW), they are also more suited to retrofitting with CO₂ capture systems.
Improving the efficiency of pulverised coal-fired power plants has been the focus of considerable efforts by the coal industry. There is huge scope for achieving significant efficiency improvements as the existing fleet of power plants are replaced over the next 10-20 years with new, higher efficiency supercritical and ultra-supercritical plants and through the wider use of Integrated Gasification Combined Cycle (IGCC) systems for power generation.
A one percentage point improvement in the efficiency of a conventional pulverised coal combustion plant results in a 2-3% reduction in CO₂ emissions.

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Uses of Coal

Access to modern energy services not only contributes to economic growth and household incomes but also to the improved quality of life that comes with better education and health services. All sources of energy will be needed to meet future energy demand, including coal.

What is Coal used for?

Coal has many important uses worldwide. The most significant uses of coal are in electricity generation, steel production, cement manufacturing and as a liquid fuel. Around 6.6 billion tonnes of hard coal were used worldwide last year and 1 billion tonnes of brown coal.
Since 2000, global coal consumption has grown faster than any other fuel. The five largest coal users - China, USA, India, Russia and Japan - account for 76% of total global coal use.
Different types of coal have different uses. Steam coal - also known as thermal coal - is mainly used in power generation. Coking coal - also known as metallurgical coal - is mainly used in steel production.
The biggest market for coal is Asia, which currently accounts for over 67% of global coal consumption; although China is responsible for a significant proportion of this. Many countries do not have natural energy resources sufficient to cover their energy needs, and therefore need to import energy to help meet their requirements. Japan, Chinese Taipei and Korea, for example, import significant quantities of steam coal for electricity generation and coking coal for steel production.
Other important users of coal include alumina refineries, paper manufacturers, and the chemical and pharmaceutical industries. Several chemical products can be produced from the by-products of coal. Refined coal tar is used in the manufacture of chemicals, such as creosote oil, naphthalene, phenol, and benzene. Ammonia gas recovered from coke ovens is used to manufacture ammonia salts, nitric acid and agricultural fertilisers. Thousands of different products have coal or coal by-products as components: soap, aspirins, solvents, dyes, plastics and fibres, such as rayon and nylon. Coal is also an essential ingredient in the production of specialist products:

• Activated carbon - used in filters for water and air purification and in kidney dialysis machines.
• Carbon fibre - an extremely strong but light weight reinforcement material used in construction, mountain bikes and tennis rackets.
• Silicon metal - used to produce silicones and silanes, which are in turn used to make lubricants, water repellents, resins, cosmetics, hair shampoos and toothpastes.

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Coal Mining

Over 6185 million tonnes (Mt) of hard coal is currently produced worldwide and 1042 Mt of brown coal/lignite. The largest coal producing countries are not confined to one region - the top five hard coal producers are China, the USA, India, Australia and South Africa. Much of global coal production is used in the country in which it was produced; only around 15% of hard coal production is destined for the international coal market.

Surface Coal Mining Operations & Mine Rehabilitation

Mining Methods

Coal is mined by two methods:

• surface or 'opencast' mining
• underground or 'deep' mining

The choice of mining method is largely determined by the geology of the coal deposit. Underground mining currently accounts for a bigger share of world coal production than opencast; although in several important coal producing countries surface mining is more common. For example, surface mining accounts for around 80% of production in Australia; while in the USA it is used for about 67% of production.

Surface Mining

Surface mining - also known as opencast or opencut mining - is only economic when the coal seam is near the surface. This method recovers a higher proportion of the coal deposit than underground mining as all coal seams are exploited - 90% or more of the coal can be recovered.
Large opencast mines can cover an area of many square kilometres and use very large pieces of equipment, including:

• draglines, which remove the overburden
• power shovels
• large trucks, which transport overburden and coal
• bucket wheel excavators
• conveyors

The overburden of soil and rock is first broken up by explosives; it is then removed by draglines or by shovel and truck. Once the coal seam is exposed, it is drilled, fractured and systematically mined in strips. The coal is then loaded on to large trucks or conveyors for transport to either the coal preparation plant or direct to where it will be used.

Underground Mining

There are two main methods of underground mining: room-and-pillar and longwall mining.

Room & Pillar Mining

In room-and-pillar mining, coal deposits are mined by cutting a network of 'rooms' into the coal seam and leaving behind 'pillars' of coal to support the roof of the mine. These pillars can be up to 40% of the total coal in the seam - although this coal can sometimes be recovered at a later stage.

Longwall Mining

Longwall mining involves the full extraction of coal from a section of the seam, or 'face' using mechanical shearers. A longwall face requires careful planning to ensure favourable geology exists throughout the section before development work begins. The coal 'face' can vary in length from 100-350m. Self-advancing, hydraulically-powered supports temporarily hold up the roof while coal is extracted. When coal has been extracted from the area, the roof is allowed to collapse. Over 75% of the coal in the deposit can be extracted from panels of coal that can extend 3km through the coal seam.
Technological advancements have made coal mining today more productive than it has ever been. To keep up with technology and to extract coal as efficiently as possible modern mining personnel must be highly skilled and well-trained in the use of complex, state-of-the-art instruments and equipment.

Top Ten Hard Coal Producers (2011e)
PR China	3471Mt	Russia	334Mt
USA	1004Mt	South Africa	253Mt
India	585Mt	Germany	189Mt
Australia	414Mt	Poland	139Mt
Indonesia	376Mt	Kazakhstan	117Mt

Source: International Energy Agency 2012

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Where is Coal Found?

It has been estimated that there are over 861 billion tonnes of proven coal reserves worldwide. This means that there is enough coal to last us around 112 years at current rates of production. In contrast, proven oil and gas reserves are equivalent to around 46 and 54 years at current production levels.

Coal reserves are available in almost every country worldwide, with recoverable reserves in around 70 countries. The biggest reserves are in the USA, Russia, China and India. After centuries of mineral exploration, the location, size and characteristics of most countries' coal resources are quite well known. What tends to vary much more than the assessed level of the resource - i.e. the potentially accessible coal in the ground - is the level classified as proved recoverable reserves. Proved recoverable reserves is the tonnage of coal that has been proved by drilling etc. and is economically and technically extractable.

Definitions

Resource	The amount of coal that may be present in a deposit or coalfield. This does not take into account the feasibility of mining the coal economically. Not all resources are recoverable using current technology.
Reserves	Reserves can be defined in terms of proved (or measured) reserves and probable (or indicated) reserves. Probable results have been estimated with a lower degree of confidence than proved reserves.
Proved Reserves	Reserves that are not only considered to be recoverable but can also be recovered economically. This means they take into account what current mining technology can achieve and the economics of recovery. Proved reserves will therefore change according to the price of coal; if the price of coal is low proved reserves will decrease.

Over recent years there has been a fall in the reserves to production (RP) ratio, which has prompted questions over whether we have reached 'peak coal'. Peak coal is the point in time at which the maximum global coal production rate is reached after which the rate of production will enter irreversible decline. However, recent falls in the RP ratio can be attributed to the lack of incentives to prove up reserves, rather than a lack of coal resources.
Exploration activity is typically carried out by mining companies with short planning horizons rather than state-funded geological surveys. There is no economic need for companies to prove long-term reserves.
All fossil fuels will eventually run out and it is essential that we use them as efficiently as possible. Coal reserves could be extended further through a number of developments including:

• the discovery of new reserves through ongoing and improved exploration activities;
• advances in mining techniques, which will allow previously inaccessible reserves to be reached.

Additionally, significant improvements continue to be made in how efficiently coal is used so that more energy can be generated from each tonne of coal produced.

Coal Exploration

Coal reserves are discovered through exploration activities. The process usually involves creating a geological map of the area, then carrying out geochemical and geophysical surveys, followed by exploration drilling. This allows an accurate picture of the area to be developed. The area will only ever become a mine if it is large enough and of sufficient quality that the coal can be economically recovered. Once this has been confirmed, mining operations begin.

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What is Coal?

Coal formation began during the Carboniferous Period - known as the first coal age - which spanned 360 million to 290 million years ago.

Coal is a fossil fuel and is the altered remains of prehistoric vegetation that originally accumulated in swamps and peat bogs.
The energy we get from coal today comes from the energy that plants absorbed from the sun millions of years ago. All living plants store solar energy through a process known as photosynthesis. When plants die, this energy is usually released as the plants decay. Under conditions favourable to coal formation, the decaying process is interrupted, preventing the release of the stored solar energy. The energy is locked into the coal.
Coal formation began during the Carboniferous Period - known as the first coal age - which spanned 360 million to 290 million years ago. The build-up of silt and other sediments, together with movements in the earth's crust - known as tectonic movements - buried swamps and peat bogs, often to great depths. With burial, the plant material was subjected to high temperatures and pressures. This caused physical and chemical changes in the vegetation, transforming it into peat and then into coal.

Coalification

The quality of each coal deposit is determined by:

• varying types of vegetation from which the coal originated
• depths of burial
• temperatures and pressures at those depths
• length of time the coal has been forming in the deposit

The degree of change undergone by a coal as it matures from peat to anthracite is known as coalification. Coalification has an important bearing on coal's physical and chemical properties and is referred to as the 'rank' of the coal. Ranking is determined by the degree of transformation of the original plant material to carbon. The ranks of coals, from those with the least carbon to those with the most carbon, are lignite, sub-bituminous, bituminous and anthracite.

Types of Coal

Initially the peat is converted into lignite or 'brown coal' - these are coal-types with low organic maturity. In comparison to other coals, lignite is quite soft and its colour can range from dark black to various shades of brown.
Over many more millions of years, the continuing effects of temperature and pressure produces further change in the lignite, progressively increasing its organic maturity and transforming it into the range known as 'sub-bituminous' coals.
Further chemical and physical changes occur until these coals became harder and blacker, forming the 'bituminous' or 'hard coals'. Under the right conditions, the progressive increase in the organic maturity can continue, finally forming anthracite.
In addition to carbon, coals contain hydrogen, oxygen, nitrogen and varying amounts of sulphur. High-rank coals are high in carbon and therefore heat value, but low in hydrogen and oxygen. Low-rank coals are low in carbon but high in hydrogen and oxygen content.
Different types of coal also have different uses, as shown in the diagram above.

Documents

• The Coal Resource: A Comprehensive Overview of Coal
  

Read more on the WCA blog Extract

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coal news and market

"Coal News and Markets Report" summarizes spot coal prices by coal commodity regions (i.e., Central Appalachia (CAPP), Northern Appalachia (NAPP), Illinois Basin (ILB), Powder River Basin (PRB), and Uinta Basin (UIB)) in the United States. The report includes data on average weekly coal commodity spot prices, total monthly coal production, regional monthly coal production, electric power sector coal stocks, and average cost of metallurgical coal at coke plants and export docks. The historical data for coal commodity spot market prices are proprietary and not available for public release.

Average weekly coal commodity spot prices (dollars per short ton)
Week Ended	Central Appalachia 12,500 Btu, 1.2 SO2	Northern Appalachia 13,000 Btu, <3 .0="" so="" sub="">2

Illinois Basin
11,800 Btu,
5.0 SO₂ Powder
River Basin
8,800 Btu,
0.8 SO₂ Uinta Basin
11,700 Btu,
0.8 SO₂ 21-Aug-15 $48.60 $51.90 $34.35 $11.55 $39.75 28-Aug-15 $48.60 $51.90 $34.35 $11.55 $39.75 4-Sep-15 $48.60 $51.90 $34.35 $11.55 $39.75 11-Sep-15 $48.60 $51.90 $34.35 $11.55 $39.75 18-Sep-15 $48.65 $51.95 $34.35 $11.55 $39.70 Source: With permission, SNL Energy
Note: Coal prices shown are for a relatively high-Btu coal selected in each region, for delivery in the "prompt quarter." The prompt quarter is the quarter following the current quarter. For example, from January through March, the 2nd quarter is the prompt quarter. Starting on April 1, July through September define the prompt quarter. In the column headings, the Btu value is per pound and the SO₂ value is percent per pound. The historical data file of spot prices is proprietary and cannot be released by EIA; see SNL Energy.

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PENAWARAN KERJASAMA TAMBANG

Bersama ini kami sampaikan penawaran Join Operation (JO) untuk KP :
PT. BPC, Kutai Kertanegara- KALTIM
- Luas Lahan : 1.250_Ha
- Hauling : +/- 9 Km
- Calorific ADB : 55-53 sampai 56-58
- Calorific ARB : GAR_40-42 dan 42-44-46
- Deposit : 4,000,000 MT
- Royalty KP : Rp. 80,000
Meliputi, all
1. SKAB.
2. Jmrk.
3. Komdev.
4. Pembebasan Lahan/PPH.
Rincian Fee Rp. 65,000 untuk :
1. Fee Jalan
2. Stock Pile & Crusher
3. Timbang
4. Jetty / Pelabuhan, Tongkang : 270 Feet
TOTAL = Rp.165,000.- / MT
Royalty tersebut di atas include Batubara sudah sampai di Ponton,, Loading Tongkang.

Note : Data-data dan Negosiasi dapat dilaksanakan setelah kami terima LOI dari calon investor, terimakasih
22 September 2015

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JUAL IUP OP BATUBARA KALORI 5000 UP

DENGAN CADANGAN 40.000.000 MT minat silahkan kontak kami

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TAKE OVER IUP OP KALORI 5500 DENGAN LUAS AREAL 5000 HEKTAR DENGAN CADANGAN JUTAAN MT

 yang minat silahkan kontak kami

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DI TAKE OVER TAMBANG KALORI 5500

Yang minat silahkan kontak kami

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PROJECT KALORI 5500

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BATUBARA KALORI 5500

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