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Coal Mining - Science topic

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Artificial dam and coal pillar dam of underground reservoir in coal mine have great differences in material, thickness and stress. In addition to establishing similar model, how to carry out test to study the stability of their combination?
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GOOD QUESTION!
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I am doing research that is required to do simulation for pillar strength and FOS of pillars in the waterlogged areas using FLAC3D, but I am new to this software, can anyone help me with the geometry development of a coal mine panel and code that I can use to do the simulation? I will really thankful if someone can please help me with this code and the processes leading to such simulation. Thanks
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All details about FLAC3D including geometry can be found in Users' MAnual. You can also try F2F (build the geometry with meshing in Phase2) or FLAC2D with intrusion option then export to 3D). Unfortunately you have to practice. Step-by-step videos can be found in Youtube
My advise is firstly, to build the model as simple as possible and then correct the model details (mine roadways, gobs, the powered roof support, etc) due to the actual conditions
here are some examples for you to check out
1. Numerical Investigation of Roof Stability in Longwall Face Developed in Shallow Depth under Weak Geological Conditions
2. An investigation of longwall failure using 3D numerical modelling – A case study at a copper mine
Good luck
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I am trying to study the application of large capacity lithium iron phosphate battery in coal mine power system, but there is no suitable data set. I will be grateful if any one can introduce similar data set.
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Any power source used in a hazardous environment would need to go through appropriate approvals before it is used in the specified environment.
Large capacity cells produce a challenge when the short circuit current, in an untoward event, would exceed the required heat limits. You may have to work with your certification agency like ATEX (UK) to ensure the operation is redundantly safe.
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I am working on my dissertation, on the topic of energy effisient benchmarking of the iron-ore mines in Ukraine. I am interesting data about electricity consumption and ore production in the iron ore mine, for compare with Ukrainian mines.
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Yes, we have just data from China.
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Dear Manisha,
thank you for posting this. I am wondering to whom exactly the author of this article is referring to when talking about "Germany" (as in: "Germany portrays itself as [...]") - the people of Germany (> 80 mio.!), the present federal government, the last federal government, the ruling three parties ("traffic light coalition"), the government of NRW (where much of this story is situated)? I could go on and on.... I realize that journalists are always after a catchy headline. But sometimes the real world out there is FAR more complex than a headline suggests...
Respectfully from Berlin,
Julius
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I am able to find only few papers related to trace element concentrations in coal and coal dust. Please suggest a few articles regarding the such works.
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Have you tried the search function in ResearchGate for publications?
Scrolling down a few responses yields several coal dust specific references.
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I would like to know that why post-mining sites are good locations for studying long-term dynamics of soil fauna. For starting a new research in this area, what new cases are still remained unknown to be studied or even poorly understood.
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Zymogenous microbial proliferation are more in post mining sites. I think a new area of research could be to study the nutrient dynamics (microbial transformation) of Zn, Fe, Mn etc. With various oxidising microbes.
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Recently "dust pollution" has become one of the main problems in my country (Iran). We know that both of  "roof garden" and "green wall" can absorb the dust pollution, but I need to know which of them can absorb more than the other (in the same condition from the area and the location).
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Roof garden and green wall both equally contribute to mitigate dust pollution.
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With coal mines still being planned and opened with 30-40 year lives, is coal seam gas (CSG) a real clean option or is it just as dirty as coal for our global power stations? Most CSG wells have lives of up to 15-25 years. When are we going to take other energy sources, such as solar and wind seriously? Can they be taken seriously as the petroleum industry buys shares into renewable energy sources and places them on the back burner until expensive lead in costs for coal and gas mines and wells can be recouped?
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Many thanks for your answers. My best regards, Joseph
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Hello everyone,
I have to characterize muck-pile in order to measure its impact on loading machine performance, if its relevant to you please help me.
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For the repose angle and bulk density is not difficult. From a little conic pile, you can measure the perimeter, calculate the radius; measure the height and than calculate the angle. There are in literature some ways to determine bulk density. See:
Lopez, J.; Vercik, A.; Costa, E.J.X. Meios granulares e experimentos simples para a sala de aula. Rev. Brasileira de Ensino de Física, v.30, n.1. 2008.
Lopez, J.; Demarchi, T.; Akamatsu, M.; Vercik, A. Estudo comparativo de algumas propriedades dinâmicas de líquidos e grãos na sala de aula. Revista Brasileira de Ensino de Física, v.32, n.1. 2010.
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Please help me understand results of size analysis using WipFrag. Anyone having experience of WipFrag or split desktop please let me know here or through email: ibrahim.min@uetpeshawar.edu.pk
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Here is the virtual sieving. Differential sieving is shown in red. When summing up all the columns, you get 100%. The blue line represents the cumulative distribution. X-axis dimensions are in logarithmic scale. The data in the window in the upper left corner mean: Cu - Coefficient of Uniformity = D60/D10, a measure of the slope of the cumulative weight % curve between the 60- and 10-percentiles. Dn - Nominal diameter, or equivalent spherical diameter, i.e. the diameter of a sphere with the same volume as that computed for the fragment. D10, D25 etc. - Percentile sizes. For example D10 is the ten-percentile, the value of De for which 10% by weight of the sample is finer and 90% coarser. In terms of sieving, D10 is the size of sieve opening through which 10% by weight of the sample would pass. D50 - The Median or 50-percentile, the value of Dn for which half the sample weight is finer and half coarser. Blocks - Number of net elements detected in the NET image. Max - Maximum size of fragment in the image [Dn (m)]. Mean - Arithmetic mean (average) fragment size, equal to the sum of all equivalent spherical diameters divided by the total number of particles [Dav (m)]. Min - Minimum size of fragment in the image [Dn (m)]. Mode - Most common sized particle, the geometric mean Dn size class interval for the class containing the greatest number of net elements (fragments) [Dn (m)]. N - Rosin-Rammler (and Gaudin-Schuhman) Uniformity Coefficient, equal to the slope of the Rosin-Rammler straight line fitted to the data in log-log coordinates. Sphericity Dn/Ds, the ratio of equivalent spherical diameter to the diameter of a circumscribing sphere (long axis of the fragment). stdev - Standard deviation of fragment size Dav. Xc - Characteristic Size, the intercept of the Rosin-Rammler straight line fitted to the WipFrag Dn data in log-log co-ordinates. This is equivalent to the D63.2. Xmax - Gaudin-Schuhman characteristic size, the intercept of the 100 % passing and the slope of the Gaudin-Schuman straight line. If you have any questions, write to me! Good luck!
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Dear researchers,
Please tell me quick measuring method of bucket-fill factor on site without interrupting operations.
Thanks
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I plan to open coal mine in Hungary for material use of coal and CO2
I have the inventory for rare earths, and there are a lot of articles in the internet
but no practical application with profitability figures
I'd like to have a lead on that
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Profitability of RE extraction is commercial in confidence - that means, only the organisations doing the work will have accurate figures. Do you have all the chemical steps and stages for your extraction process? Do you have figures for their costs? This is going to be a major task, but best wishes for your work!
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Mankind's ideas of energy production must be re-thought in order to survive... The relyance on fossil fuels or nuclar energy does not help. All sources of energy should be thought about, so tidal energy is OK, but not very efficient. It has be shown to work (e.g. in the Netherlands and France in estuaries of rivers)... Wind energy is efficient in costal areas but has been depending on state funding... But do you honestly think that coal mining or the production of nuclear energy/Waste is not depending from state funding/subsidies?
An introduction can be seen by the Open University, see URL:
Do you have helpful ideas or thougths?
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All of these advances inevitably led to the assumption that new resources were not needed in the development process. This is due to the fact that based on fossil fuels - on the other hand.In reality, this contrast is far from straightforward and requires more thoughtful study. Carbon dioxide capture and storage (CCS) and methane management technologies at all stages of the increment in the cost of energy from fossil sources can help fulfill large-scale tasks to reduce CO2 emissions while fossil fuels are still part of the energy system. Thus, these measures allow fossil fuels to become part of the solution, rather than remain part of the problem. A rational economy plays an important role in the energy systems of each technology.
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I am looking for the required #water #quality levels/criteria for a "non-drinking" water (or #recycled #wastewater) that should not be exceeded when using that water for #mine #operations? Any info is welcome.
I know seawater has been used in Copper mines in Chile. Any other examples of other "non-drinking water" use in mines?
Info on Underground Mines... and especially in the coal mining space is highly appreciated.
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Testing of mine water is needed and accordingly online filter and online anti-corrosive additive can be added.
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I am working on designing a stimulated layout that is scalable and optimized for thin coal seams in Punjab, Pakistan. The average thickness of coal seam is 3-9'' that's why there is low production in coal mines. So it is difficult to mine out it in valuable price. I want to optimized the production of that coal mines by designing a optimized layout. Kindly share your experiences. Thank you!
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Dear Ali Ejaz Qureshi .
I am very glad that you are working in this direction.
I am also engaged in the optimization of technological schemes for coal mines with low-power seams.
In Ukraine, the thickness of most layers is 0.8-1.2 m.
A new article on optimizing process diagrams is coming soon.
Here is the link to my Google Scholar profile https://scholar.google.com.ua/citations?user=ebUy32AAAAAJ&hl=ru
I can advise the work of such authors:
Look magazine Mininh of Mineral Deposits http://mining.in.ua
I'll be glad to help. Here is my mail khorolskiyaa@ukr.net
Good luck
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Is there any possibility to emit mercury from coal mines except coal fires?
as we all know that anthropogenically after combustion of coals mercury emits into atmospher from coal fired thermal power plants.But I want to know from coal mines.
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Adel Badri but the paper is related coal combustion but I need emission rate from coal mines Sir.
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Numerical modelling has been widely used to analyze the various type of issues related to the underground mining and tunnelling: subsidence induced by longwall coal mining; stresses computation around longwall coal face etc.
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Now a day the numerical analysis offer many simulations of mining technologies used in mining practices. My recommend is if you use sophisticated numerical analysis than check results with adequate in situ measurements.
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After dust control measures were put in place the incidence of progressive massive fibrosis declined, but recently it is making a come back in coal mine workers. What do you think is the cause and how to bring the incidence down again ?
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I believe that the coal mine industry have been moved from the west to the east, to countries where HSE prevention is not a main priority of the companies.
If the question is about the west, I remember to seeing statistics on the increase of silicosis in the ornamental stone industry with the new products of aggregates, and the workers of these kind of companies than work cutting these materials
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I'm searching for open access and peer reviewed international journal (obviously of high quality and with Impact Factor) to publish research on development and operation for mineral deposits. Best Regards Andrey Khorolskiy
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Dear Pavel,
Always open to cooperation.
My e-mail: khorolskiyaa@ukr.net or additional e-mail: andreykh918@gmail.com.
Regards.
Andrii
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It is known that the presence of groundwater can significantly impact any coal mining operation.
On the contrary,
Whether coal mining operation has a significant negative impact on groundwater resources?
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According to a research the groundwater quality decreases with depth.Groundwater flowing through abandoned coal mines often has depressed pH levels and elevated hydrogen sulphide, iron, aluminium and nitrates.
Such water is also typically high in copper, zinc, mercury, and lead. Impacts of hydrogen sulphide in drinking water yet hydrogen sulphide is
commonly found in the groundwater near coal mines. This gas is known to cause detrimental respiratory illness in humans.However, the systemic effects of ingesting hydrogen sulphide are obscure, and studies correlating hydrogen sulphide to health have been restricted to lab animals.
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Hi everyone
I am looking for some studies or books in (metal or coal) pit lakes that have summarized (if possible) the combined effect of oxygen physical entertainment into bottom thermal zones (eg monimolimnion) and the impact of biogeochemical processes (eg methane, ammonia and hydrogen sulfide oxidation).
Most studies seem to assess these two processes separately or by hydrodynamic modelling. While the latter helps, modelling requires continuous validation. I would be interested in (field) studies integrating both mechanisms to asses the oxygen dynamics (i.e oxygen supply vs oxygen demand).
A great example of what I am looking is:
Thanks – hope to get an answer soon
Daniel
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Can anyone please provide me papers on the characterization of Heavy Metals or trace elements or PTEs contents in mine water pertinent to coal mines of China and US, especially of Gondwana coals?
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Dear colleague that textbook may help you to differentiate trace elements and their occurence in coal mine (Swaine, D. J. (1991). Trace Elements in Coal.
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Hello all,
I'll start by describing the scenerio in which I need help. There is a coal mining site. Hundreds of trucks carry coal to the dump site every day using top-open containers. I need to calculate the volume of coal loaded in each truck at a certain checkpoint in real time using a LiDAR sensor. Basically how it should work is, the empty truck while moving slowly (around 5 kmph) will be scanned using LiDAR sensor before loading it up which will give volume V1 of the truck. Then after loading the truck, again it will be scanned while moving slowly which gives volume V2. So with V2 - V1, we have the volume of the coal contained in the truck.
Now the question is "What LiDAR sensor system can help me achieve this ?"
I have mentioned a video link to show how it should work of a company which has already implemented it. But I need to create a low cost system to do the same.
Please let me know if you think of something which might help getting closer to the solution.
Thanks
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As long as the measurement is made from near the truck, just about any lidar should be capable of such a simple measurement. In fact, I'd look into passive imaging methods that would be simpler, with lower cost.
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In underground coal mine, an intact coal barrier is left between active and abandoned mine. Abandoned mine are flooded after long time of mining due to groundwater and water used during mining for dust suppression purpose. Width/thickness of an intact coal barrier is very critical for mine failures and to protect active mine from flooded abandoned mine. Therefore, if anyone can suggest me journal/conference paper(s) or books related to this topic that would be great.
Thank you in advance
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Sunny,
It has lot of good information and helped me a lot for pillar design.
Thank you
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briefly explain the reasons
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Two aspects to be considered with regard to subsidence is the information of sub-surface geological formation (mainly the clay seams) and the hydraulic pressure of groundwater (artesian / confined condition).
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How can we measure Soil Organic Carbon and Coal Carbon in soil sample of sites around coal mines.
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Please get soil samples sieved with < 0.2 mm diameter; this may possibly eliminate coal carbon from soil OC. It is expected that coal C may have diameter > 0.2 mm. Just try.
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I have researched the power field more decades. It is strange to me why distortion power is not measured, registered and pay. From my researches in drives (air conditioners, elevators, drives in coal mines), so as in lighting, the consumption of distortion power absolutely is not negligible.
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Distortion power is not captured in vertical transportatio, reason being it may be very momentary and also under dynamic situations.very less.
As mentioned by professor Mircevski we measure S(Kva) and Q ( kvar) , the source need to be identified and corrective actions to be implemented
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Can anyone suggest me, how to use stable isotopes viz., deuterium and oxygen-18 in transport contamination modelling by the aid of Visual MODFLOW Software and the study pertinent to coal mine impact assessment of groundwater regime. Also, please share relevant papers or information.
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This is area of safety research work, carrying out in underground coal mine.  How to identify various risk factors and behavioural factors to analyse role of health and safety in underground coal mine.
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What makes underground coal mining stand out from most other industrial environments is the capacity for disasters involving multiple fatalities. In Queensland underground coal mines, there have been 90 fatalities since 1970. Of these 90, two-thirds or 60 were the result of multiple fatality accidents. Incidents that have resulted in multiple fatalities in Queensland mines include  fires, gas explosions, gas poisoning and large scale rock falls. In other jurisdictions flooding has also caused several accidents. This is usually due to breaking through into old abandoned workings as at Gretley Mine in New South Wales in 1996, at the Porter Tunnel in Pennsylvania in 1976 and Lofthouse mine in the UK in 1973. It is noteworthy that at Moura number 2 Mine in Queensland in July 1994, management closed the entire mine for two days and engaged all employees in an intensive workshop to analyse the risks at the mine and propose defensive measures. The result was a 70 page report covering many items - but conspicuously .missing from the analysis was a gas explosion ignited by spontaneous combustion.  Just a few weeks later an explosion ignited by spontaneous combustion in a sealed off area of the mine resulted in 11 deaths and closure of the mine. In my opinion, analysis of risks in underground coal mining should always give top priority to the possibilities for disaster,. and never ever dismiss them as "low probability". In many accidents including Moura, management and employees were well aware of the risks and the means to mitigate them, but through long exposure had become blase. An important component of any safety program is an inspection and quality control program to ensure mitigation measures are properly and thoroughly implemented.
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I am working on a project related to coal mines at stream reach watershed level. Vegetation cover has been so dynamic. For example, they mine some area( vegetation loss) in 1991 then reclaimed the same area in 1993. they mine some other part of the watershed in 1994 then reclaimed 1997. I would like to measure vegetation growth with cumulative NDVIs. My idea is using yearly summer NDVIs from LandSat and calculate the cumulative NDVIs on a pixel base for different watersheds. Do I need to make any adjustment from year to year and also from Land-Sat 5 to Land-Sat 7 or Land Sat 8?
If you could help, I would greatly appreciate it
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As the band intervals are different for different Landsat Satellites the calculated NDVI will be effected based on these differences. For example, lower vegetated areas has higher NDVI values with Landsat 8 than Landsat 7. About this issue, you can check these articles:
Compare NDVI extracted from Landsat 8 imagery with that from Landsat 7 imagery
Comparison of the Continuity of Vegetation Indices Derived from Landsat 8 OLI and Landsat 7 ETM+ Data among Different Vegetation Types
On the other hand, what do you want to achieve by measuring vegetation growth? As I understand you want to use only 1 imager per year. If so you can use change detection techniques in order to show the vegetation growth over mined areas.
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INSULATION AGING & GREEN FOAM
William R. Harris, P.E.
Green foam is light cream in color and if you placed a chunk of it next to other rigid
polyurethane foams, you wouldn’t see any difference. In fact the foam itself has not changed. 
Link provided below
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Why not blue or red or maybe green?
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And occasionally manufacturers go through a trend of differentiation such as the use of a "white wall" (decorative contrast color applied to the side surface of the tire). These were quite stylish on early Buicks etc. I think any manufacturer who tried to bring back a white wall tire today would be ridiculed.
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for drought management
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Is to be applied in the pampean region Argentina.
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i agree with Rafael Anleu  
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How to analyse the stable isotopes N-15 in coal mine soil samples?
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For  soil N-15 samples, i just dry and gried them as they are without any decalcification or acidification procedure.  After that, i send soil samples for IRMS (Isotope-ratio mass spectrometry) analysed and basically that's it.
Hope it helps you
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In DMC(Dense Medium Cyclone), if we use silica sand/silica fumes rather than magnetite for processing of coal, then how the media is recovered after processing? 
What are the other different medias (except magnetite/Ferro silicone/silica sand or silica fume) that are used for dense medium separation of mineral / coal ? 
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Dear Bibhu
I'm really a placer gold mineral separation expert, not coal.
I suggest the silica sand would be recovered by either gravitational settling (eg jig or pan or sluice) or by surfactant floatation.
Robin
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Cover surface consists of 8-24'' dia. cobble-boulder, unknown depth. Would like to characterize known collapsed adit and hydrogeologic interaction with mine waste in the safest way possible. Thank you for your consideration.
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No silver bullet in geophysical techniques generally.  It very much depends upon the surface and depth to the adit.  If the adit is under the water table and relatively shallow (sy 10m or so) then I'd suggest an EM survey (EM-31 or EM-34 for example).  Geoelectrical surveys such as resistivity and IP may be useful wrt acid mine activity; however, interpreting such data can be very, very difficult.  The cobble-boulder overburden sounds a bit odd.  The most effective means I know of to find a water filled tunnel or such is to use misse-a-la-masse or similar with a magnetometer (MMR method).  The techniques places an electric current into the tunnel and another electrode far away.  The electric current tends to follow the tunnel water out towards the far electrode.  The surface electric field or magnetic field (measure the difference between current on and then off to remove background fields) indicate the presence and extent of current flow..  I have used such techniques in mapping tree root zones and with an UG research project to find water channelling near bridge supports during flooding - usually hopeless targets with conventional geophysical tools. Modern adaptations of the idea are used in "pipe finder" tools used by engineers to find buried pipes in industrial areas with a lot of other buried clutter.    
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Does anyone have a chart of the general cost per meter for wire cables (used in hoisting systems) for some diameters? It's for a simulation. Thank you very much and have a great day.
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no manufacture publishes prices for the reasons of being undercut by competitors.
If you go to Scaw Metals website you will find a brochure of all types and sizes of rope. You will then have to contact them for indicative prices.
DF]S14080 Shaft Mining Brochure Tail Ropes WEB - Scaw Metals Group
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Normally researchers prefer to study drill core sample, but for an individual student it is sort of difficult to acquire core samples, in that case, is it possible to take bulk sample from any kind of mining and take a core sample from that bulk sample in lab?
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Indirect method can never be a substitute for the direct method however, from a coal sample after preparing a core  and after having proximate analysis and adsorption isotherm values the Kim's formula can be used. One may find the results with significant level of uncertainty.
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In order to know the area of major fall from its impact parameters I wan to classify data in three categories like Low, Medium, High. The parameters are as follows :
Area of exposure 0-10,000sqm, Depth of cover 0-110 m, RMR 65, Roof cavability -1.5 , Roof convergence - 1.5 m,
Area of Major roof fall 0- 3400 sq m. This classification based  to Indian DGMS standards it is helpful.
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Roof depends on the combination of factors .You can read the paper of Smith, A. D. and also of Mark & Molinda for your quarry. Hope you will find answer.
1. Mine Roof Condition and the Occurrence of
Roof Falls in Coal Mines
Smith, A. D.
The Ohio Journal of Science. v84, n3 (June, 1984), 133-138
2. The Coal Mine Roof Rating in Mining Engineering
Practice by C. Mark & G. M. Molinda 2003 University of Wollongong
Research Online
However, I would like to mention that one single discontinuity  (especially sub-horizotal to horizontal) if not identified during exploration , in rock mass may override all calculations based on general rating.
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I am doing my dissertation and it has been difficult to obtain that info.
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Dear Toribio,
I visited on of the highly reducing lake in Iraqi Kurdistan, northern Iraq. It is not an active coal mining but it can help to get general geological and environmental setting for reducing environment and studying bio activity within this kind of environment.
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information on research papers that have dealt with this problem before
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we have some papers on mining waste land development
may be useful to you as a application.
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I have a flac3D model of coal mine. The panel is of 200*200m size. Boundary of model taken to be 200m away from boundary of the panel on all sides. Progressive face advance is being carried out alongwith caving. How can I be sure that boundary effects are not altering my stress distribution?
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Increase the size and do several parametric study to ensure the stress distribution doesn't change with the model size. 
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for a statistical study, we need to a data base including E, Poission ratio, Density, UCS, C, phi and Tensile strength of coal seams. for this aim, we search on papers and collect data one by one.
if you have similar data or refer to any references, please help us.
thanks
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I recently found this paper which might contain some useful references:
Yu, Vozoff and Durney: The influence of confining pressure and water saturation on dynamic elastic properties of some Permian coals, Geophysics 58 (1993) 30-38
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In underground coal mines, please give explanation impact of these parameters on roof fall in different mining methods like Bord and pillar and Longwall.
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Area of exposure gives a volumetric sense and area of roof exposure gives a geometric sense.
it means any place or point which is exposed to the under ground environment is included in area of exposure and  area of roof exposure is also an exposed area but restrict only upto the roof.
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longwall mining
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The main cause of this problem is the incorrect ventilation design during pre-feasibility/feasibility study stage. Ventilation design in a longwall mine depends solely on Specific Gas Emission (SGE), which is the amount of seam gas liberated per tonne of coal mined in a longwall panel (m3/tonne). The seam gas is usually methane, but few mines in Australia have carbon dioxide as the predominant seam gas. The main issue in calculating SGE is that most of the gases (around 90%) come from seams above and below the mined seam (remote seams), and it is extremely difficult to estimate contribution from each remote seam due to many unknown factors, such as the extend of these seams that is fractured by longwall caving, virgin gas content of each of these seams, and the amount of gas liberated by each remote seam (which is a function of ground water pressure). There are many models to estimate SGE but all of them use assumptions to cover the unknown factors described before. Experience in Australia found that they usually underestimate SGE (which subsequently underestimate the amount of airflow and gas drainage), so engineers usually apply a correction factor of 1.5 to the output of these models. Modelling SGE remains a main problem in designing ventilation in longwall mines up to this day.
Increasing air velocity in longwall face has a limitation, in which that the air velocity at the face has to be kept below 5 m/s in order to keep personnel comfortable and to prevent dust stirred up from the floor. For example, if the longwall face cross sectional dimension is 5 m wide and 4 m high, then the maximum airflow that can be delivered in the face is 100 m3/s. Probably the limit can be increased to 6 m/s if a very good dust suppression system is installed. In this case, the maximum airflow is 120 m3/s. The point is that you can only increase the airflow to a certain limit due to the air velocity limit at the face.
In gassy mines in Australia, ventilation alone is not adequate to control methane and carbon dioxide in return airways. Therefore, extensive gas drainage is used (pre-drainage and goaf drainage). In these mines, 60 to 80% of SGE is taken by gas drainage. Of course the caveat is cost as gas drainage is very expensive. Few mines recoup some of this cost by selling methane to generate electricity.
Bleeder airways are not used in Australia due to Spontaneous Combustion. Moreover, bleeder causes oxygen concentration in the goaf to be greater than 12%. In this situation, explosive mixture is formed (5 to 15% methane and oxygen 12 to 19%), which is very dangerous and should be avoided at the first place. These are the reasons of why I'm not a fan of using bleeder airways
Therefore, the answer to your question is first, you increase the airflow in the longwall face until the air velocity reach 5 m/s. If this doesn't work, then you will need goaf drainage, and probably in-seam pre-drainage. To desigh the drainage plant (capacity), you will have to work out SGE. I can give you a model (set of calculations) that I believe is quite accurate if you want to. Just give me your email address and I'll send it to you.
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I need to classify  Radarsat 2 and Alospalsar data set using Support vector machine. I have the 5 multi component scattering parameters layer stacked individually for Radarsat 2 and AlosPalsar. I have total of eight classes namely Urban, Dense Vegetation, Sparse Vegetation, Barren land, Harvested land, Dry water bodies, Water bodies, Coal mining area. To get the ROI's of barren land, coal mining area, water bodies and dry water bodies are difficult as it gives almost the same backscatter values in the surface scattering component. Are there any ways of classifying the above classes in the  mentioned data sets?
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I agree with Prof.Gloaguen. If the data is not matched with your objectives, kindly change it. Or try data fusion with optical data.
If you solely use the RADARSAT data, you may add textural features or decomposition methods to improve the classification. There are some methods that can help you for better spectral seperability. You may check the article below:
Effect of Different Target Decomposition Techniques on Classification Accuracy for Polarimetric SAR Data
I also suggest you to analyse the data spectral response and training data characteristic. You may define the methods more proper up to the result of it.  
See this article as well.
Haack BN, Khatiwada G; Comparison and integration of optical and quadpolarization radar imagery for land cover/use delineation. J. Appl. Remote Sens. 0001;4(1):043507-043507-16.
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Coal Mining, Ground control
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Your question is intriguing and also needs to be addressed from practical and visual investigations as well, which provide some wonderful signs of impending dangers. Roof falls are major concern for any underground mining professional. It may be interesting to note that several hours before a major fall in one of the UG coal mines, we could hear very low intensity noise from the roof before its final collapse. Also, many times by tapping the roof with an overman's wooden rod, the roof gives a husky sound instead of its characteristic sharp sound. The sides may show the signs of spalling. Also, many a times, I could witness sudden increase in water seepage from roof. Supports (timber) were also observed to buckle.
Coming to your concerns, if RMR rating is high, we can go for expansion in roof exposure area with a limited confidence,though. Cover depth definitely enhances the chance of roof fall. Hence, we need to strike an optimization among cover depth, RMR rating and the span or maximum exposure area.
Furthermore, the borehole logs of the districts, if available, should be thoroughly scrutinized for studying the nature of immediate roof layers. Acoustic emissions from the roof need to be also studied. Also, wherever possible the convergence recorders should be used in addition to seismic studies.
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In the sustainable development plan of coal mine area,How do we determine the utilization efficiency of resources in coal mining area,such as coal resources and land resources and How to measure their relationship?
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Utilization efficiency of coal resources begins with efficient recovery of mineable coal reserves from underground/open-cast  mines.Thereafter,  effective utilization of recovered coal in surface plants like Coal Handling Plants (CHP), washing plants (washeries) etc also needs to be considered;in some cases even the middlings and tailings from the washeries are re-used in power generation. Then for the thermal coals, the ash utilization also adds to the coal resource recovery efficiency.
The utilization efficiency of land resources implies that what percentage of land, environment and ecology that was disturbed due to coal mining has been restored/ reclaimed or even upgraded in comparison to its original topography. 
Ideally the ratio between the two should be 1:1.
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How Mine height plays a role in roof fall study ? can anyone help me  in providing stuff or supporting documents related mine height in coal mines in bord and pillar method.
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With increase in height the pillars become less stiff and more flexible to spalling or breakage. This, in turn, increases the chances of roof failure and falls.
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What are the newest methods in mechanization at steeply coal mine?
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Dear Mohammadi, The answer for your question is Hydro - Borehole Mining technology
details , please contact me by e-mail w.jura@wp.pl
Regards W.Jura 
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High Li concentration was found in coals from the Jungar Coalfield. We are looking for methods to extract it from coal ash.
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Many thanks!
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I am in the process of deciding to update a book on mine explosions and need to start doing some more recent research to fill in the gaps left from completing my PHD. Do you have any interested parties also welcome to discuss some ideas with me.
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Dear Dr. Johannes.
I sent a brief information of the explosion of the San Fernando coal mine in Amaga Antioquia Colombia. In coal mining Colombian  we have problems in the operation and safety mining. Several explosions have occurred in the mines in recent years.
I hope to get more information. On page NIOSH there is good information.
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Around coal mining regions,where there is a possibility of coal particles or carbonate or some other contamination of soil, Can all these affect organic or inorganic carbon of the soil?
Is these contamination hindered with soil carbon analysis? 
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The American documents describing miner's protection from the coal dust, referred to the use of grinders (shredders) for the longwall shearer; and in the coal transfer points from one conveyor to another. How big is the size of the original pieces of coal produced with the longwall shearer, and their average size?
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I am looking for developing the communication link in Indian coal mine scenario. If any one work on to this field can suggest suitable path loss model for finding the suitable signals.
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USE  SOME  GIS APPLICATIONS 
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What is difference b/w ASTM D3172 and ASTM-D5142 methods for Proxmate analysis for coal of lignite type?
whose method is accurate and how much error between them of these two methods?
Questions in Your Topics. Available from: https://www.researchgate.net/topics?askQuestion=1&tpca=1 [accessed Mar 20, 2015].
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Attached articles may be useful to you
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Dimensions? What are what? Any book or website for design and very basic force calculation? I would like a simplified design.
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I hope this attached paper may be useful.
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Hi Everybody!
I want to find Roof Fall Predictions in Coal mines. What parameters are required for finding Stand-Up time of Roof? I want to use Fuzzy Logic 
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Dr. Perumalla, you could consider using the flowing parametrs: the uniaxial compressive strength, tensile strength, and the thickness of the roof; the length and width of the extracted space of the longwall panel; the mining speed (i.e., the advance distance per day). 
D. Xuan
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The face of acid mine drainage treatment is changing.The costs of abatement of acid mine drainage are high, but the benefits to society and the environment are far greater in the long run.
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The typical methods of treatment for acidic and metal contaminated water effluent such as the Acid Mine Drainage (AMD) will always focus on either civil engineering methods, such as disposal, excavation, drainage and encapsulation or process based technologies such as effluent washing and treatment. These techniques are not environmental friendly, costly and unsustainable, thus environmental damaging. Nowadays, there is a growing need for an alternative remediation treatment that is innovative and more natural in order to prevent pollution in the environment. Therefore, in this study, a new alternative treatment, that is more organic, biodegradable and cost effective, using bone meal was presented. In this research, bone meal comprising of chicken bones were used as an alternative passive treatment to determine its potential in neutralizing and removing heavy metals from the abandoned cooper mine, Mamut Acid Mine Drainage (AMD) waste water effluent.
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Underground coal mine fire is a major problem faced by many countries. Not only does it reduce the amount of fossil fuel but also adds on to the risk of land subsidence in the area. So, is there any measures that can be taken to reduce or extinguish the coal mine fires so that we can save coal for future uses?
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By using remote sensing, one can observe earth surface and its dynamic changes. If you know the surface change related to the underground coal mine fires (if possible, e.g. ground surface subsidence and temperature variation), then you can study on whether remote sensing is able to capture such phenomena. I think you can try SAR Interferometry (InSAR) for ground surface subsidence measurements and infrared remote sensing for temperature variation inversion. Good luck and best regards.
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Goa in India is a mining belt and there are piles of mining wastes dumped
also vast land which are to be reclaimed by technological means.
similar waste lands must have been there in the whole world. it is to know in this direction more about the global technologies and systematic efforts done in this direction.
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There are several methods of reclamation of mine waste lands. Physical, chemical and biological methods.  For ecological services physical followed by biological methods of re-vegetation seems to me to be perfect for clean up of environment. You can get several publications in context in my profile. If you get trouble to download please mail me at my mail id: rajcimfr@gmail.com. Best wishes.
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In the region of the Latrobe Valley, Australia, a succession of disasters and events have occurred over the past few decades within and surrounding the open cut brown coal mines, which are directly related to extreme climate events such as heavy rainfall and fires. The most impacting being fires which entered the Morwell coal mine in February 2014 and covered the township of 14,000 people in toxic smoke for a month. Other incidents have included nearby rivers breaking banks into the open cut coal mines, and numerous cracks and sinkholes occurring in surrounding areas approaching on townships. Whilst the members of the community are dependent on the industry of coal mining for employment, the industry continues to struggle to adapt to climate change. And it is the members of its community who are left to struggle and live in its smoke because of these large company's inability to mitigate and adapt. Does change start with the members of the community? Is there something communities can do, or is their fate determined by these large companies and government policy?
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Thankyou for your response Roland. I agree that the mining  companies and their associates have a duty of care and responsibility to mitigate such events from occurring. And it is concerning when a number of events have occurred in the past, which have been attributed to 'cutting corners', lack of appropriate monitoring and implementation of prevention mechanisms in place. It is particularly concerning when a $120 million river diversion project, (which won an award for engineering excellence in allowing further expansion of the mine) failed in 2012 when the river levee banks collapsed and caused the river to flood the mine. And with the effects of climate change, the wider region is projected to have more extreme rainfall events, longer periods of  heatwaves and fire-days in the future, which surely needs to bring greater attention and urgency to the matter.
The mines and the government are responsible for their own behaviour and decisions, the community has very little if no control of that. I suppose in terms what the community can do, is adapt to the changes themselves. They can only control, what they control. And that means minimising their energy use and being more efficient, producing their own energy on site with renewable energies such as solar power. But the community is struggling, socially, environmentally, and economically because of the power stations, and a shortly imposed, but recently scrapped carbon tax. Steps are in place to try convert the region into a low-carbon economy, however the fallout in the transition process has failed to adequately allow for job losses and accommodate for the production of more jobs.
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Roof monitoring conditions for an early warning system.
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During roof deterioration, numerous small and big cracks form in the roof. Every crack formation causes electromagnetic radiation. Therefore, with cumulative record of the electromagnetic radiation, on can get an estimate of the magnitude of roof deterioration.
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See above
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I think we can minimize and also it is possible to have zero accidents in the mining, using Instruments to control the stability and events in mining, real time monitoring.
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Aside from wind blowing on mine tailings and wasting, there are many other mining activities that can also generate dust such as the removal of vegetation and topsoil, on site blasting and drilling operations, use of crushing, dry grinding and dry screening equipment, construction activities and the driving of vehicles on access and haul roads, etc.
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Particulate matter (PM) in air includes a mixture of solids and liquid droplets. PM comes in a wide range of sizes - those less than 10 micrometers in diameter (PM10) are dangerous as those can get into the lungs with every breath we take and resulting in serious health problems. PM that are less than 2.5 micrometers (PM2.5) in diameter get generated in activities like combustion in power plants, residential forest fires and some industrial processes.
Control of PM emission - Indeed it is a big issue. There are guidelines to keep the PM in ambient air under control. Plantation over loose soils, sprinkling of water over haul roads and work areas, transportation of crushed minerals in covered vehicles (or over-head closed belt systems) etc. could be done.
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See above
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Backfill is the best method for mining areas to prevent residue disposal. Back fill with construction materias waste or industrial waste materials. Another economic approach is carbonation of mining waste, residue and mine tailings
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Regards to mining.
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Also the incidence of occupational hazards among the workforce and may be pitching it against a low or normal risk occupation
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Any guidelines or sugggestions on testing that would be required to assess safety - what substances, what detection limits, how often?
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The toxicity of produced water depends on a number of factors, among them:
--what's used to produce it (what's injected) and how
--the chemical profile of the coal
--the geology of the production area
--the size and flow of the body of water into which it's discharged
These are just a few. Produced water in offshore exploration is can be quite saline with higher mineral content, therefore heavier, than the surrounding water. It can contain solubility levels of the petrochemicals with which it's in contact. Consequently, its discharge can affect benthic biota.
Guess the answer would be that more information is needed before attempting to answer the question. Hope that helped,
K
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Are you guys using stochastic modeling for costs based on ABC in lieu of the standard Fixed and Variable cost?
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We are employing Fixed and Variable cost analysis adjusted daily.
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I would greatly appreciate any key references and information about the impact of this industry and risk of fires and water catchment degradation and contamination to natural high biodiversity areas such as the Royal National Park in Australia. Thank you.
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thanks David - this approved activity is in all of the water catchment areas for Sydney and prime agricultural land is not really secure either, if the water catchments were secure then the biodiversity would be much more secure - but we're pretty much in the same boat. the health literature is about as sparse as what you are describing. its quite astonishing. I certainly appreciate your response - altho the attachment didn't attach!