Reflections on Coal Mining

By Jesse Dykstra 30/11/2010 13


Anthracite Coal.  Source: USGS

An Important Fossil Fuel

Coal is a rock that forms under intense pressure and high temperatures when plant material is buried under younger sediments over periods of millions of years. The resulting mineral has a very high concentration of carbon, and therefore is an important source of energy. Coal is the most abundant fossil fuel on earth, with an estimated 900 billion tons of recoverable reserves. In fact, even with recent advancements of clean energy technologies (such as solar and wind), coal is still the single most important source of electricity on earth. Coal is abundant and relatively easy to extract because it tends to be concentrated in the earth.

However, using coal to generate electricity is a very dirty business. Coal mining releases greenhouse gases such as methane, and it is estimated that the burning of coal has produced nearly half of the carbon dioxide in our atmosphere. Burning coal also produces nitrogen and sulphur dioxides which contribute to acid rain. Waste ash from burning coal contains high concentrations of toxic heavy metals such as mercury, lead, cadmium and arsenic, not to mention uranium and other radioactive nasties.

The United States has the largest coal reserves of any country, and is the largest consumer of electricity, both per capita, and in total consumption. The U.S. generates nearly 50% of its’ electricity from coal. Therefore it should not surprise anyone that the U.S., (also China is now the largest emitter of greenhouse gases) has refused to commit to the emission reduction targets of the Kyoto protocol.

Sources of Electricity Worldwide
Source: OECD/IEA 2006

Carbon Capture and Storage

CCS has been touted as the answer to cleaning up coal, with the potential to reduce atmospheric CO2 emissions by up to 90%. But CCS isn’t actually working on a large scale-power plant anywhere, at least not yet. This is partly due to the added cost of post-combustion CCS. Compressing, transporting and storing COis an energy intensive process, so up to 40% more coal would need to be burned to produce the same net energy. The additional infrastructure required for CCS also raises power plant costs, and uses more raw materials and energy in manufacture.

Source:
Source: Duke University

And the really big unknown is still the storage part. Scientific studies are currently underway on various options, including underground storage in suitable geological formations, storage in the deep oceans, or reacting CO2 with naturally abundant minerals such as Calcium to produce stable carbonates that stay out of the atmosphere. There are many ideas for pre-combustion and post-combustion CCS that are currently being investigated or trialled, and it will likely be years before practical cost-effective solutions become a reality, if ever.

Coal in New Zealand

At present, Coal is mined in New Zealand primarily for overseas export. Coal from the West Coast (such as Pike River Coal) is some of the highest quality (most energy-dense) coal in the world, and is used in the steel industry, both in New Zealand, and overseas in places such as India and Japan. In New Zealand we are blessed with arguably “renewable” energy sources such as hydro and geothermal, and only 10% of electricity currently comes from burning coal, compared to over 40% worldwide.

Is Coal Mining Safe?

Coal mining involved unearthing some very volatile substances, and has therefore never been a particularly safe occupation. Miners must contend with deadly poisonous gases such as hydrogen sulphide, in addition to highly explosive gases such as methane that accompany coal underground. In 1896, 65 coal miners were killed by a methane explosion in the Bruner mine on the West Coast. Modern technology and mining techniques certainly mitigate many of the risks, but coal mining continues to claim thousands of lives every year. China accounts for nearly 80% of the world’s coal mining fatalities, including a 2005 methane explosion that killed a reported 210 people in Fuxin, Liaoning province. China has recently begun to focus on capturing coal bed methane prior to mining, using new drilling technology from Australia. In the meantime, an average of 15 workers die every day in Chinese coal mines.

Source:

Following the Pike River mining disaster, New Zealand must reconsider the cost, in human lives, of extracting our coal resources. When we look at data from the U.S. Mining Safety and Health Administration, it becomes apparent that mining has become much safer in recent decades, and that the number of fatalities amongst coal miners is around 20 per 100,000 workers.  This is comparable to industries like fishing and logging.

What about in New Zealand? The latest work-related injury statistics that I could find were from a 1999 report that used data from 1985-1994 (citation). Hardly up to date information. Nonetheless, we can make a comparison to data from Australia and the US during similar time periods. The following chart is based on a 2001 article in the journal Injury Prevention:

 

 

 

 

 

 

 

 

 

 

 

   New Zealand Australia       U.S.
Industry  Deaths/100,000 Deaths/100,000 Deaths/100,000
Agriculture, Foresty, Fishing 22.3 21.8 17.5
Mining

51.3

32.7 21.7
Construction 10.8 8.6 10.5
Manufacturing 2.5 2.5 2.5

 

Based on that rather dated data, it appears that working in the mining industry in New Zealand is indeed a risky business. Over 50 fatalities per 100,000 workers, which is more than double the U.S. rate. Of course, the actual number of people working in the mining industry in New Zealand at any given time is relatively small, and tragedies like Pike River grasp the attention of the nation.

Mining is an important industry in New Zealand, particularly on the West Coast, where mining holds its’ own against the mighty tourism and dairy industries. Mining is “in the blood” of many coasters. But do the economic rewards justify the bloodshed? Perhaps now is a good time for New Zealand to take a hard look at the long-term future of coal mining. This country is blessed with an abundance of alternative energy sources, such as hydro, and geothermal, and while coal is an important export product, it isn’t a major component of our current energy use. As a long-term alternative to coal (and gas), New Zealand has great potential to develop clean, renewable energy options, such as harnessing solar, wind and wave energy.

The high quality coal on the west coast is a valuable economic resource. There will always be an industry keen to extract it. And there are large deposits of low quality lignite coal in Southland that Solid Energy would like to extract (https://sciblogs.co.nz/hot-topic/2010/11/06/licking-lignite/). But in New Zealand today, I doubt that we want huge open pit mines plastered all over the West Coast, or the rolling farms of Southland. We prefer the idea of “precision” or “surgical” mining, that operates mostly underground, with minimal impact on the surrounding environment. We want the type of mining hyped by Energy and Resources Minister Gerry Brownlee, back when National thought that mining the Coromandel might be an idea palatable to New Zealanders. Sadly, the Pike River tragedy suggests that the industry standards and technology required for safe precision mining in New Zealand either don’t exist yet, or aren’t being properly implemented.


13 Responses to “Reflections on Coal Mining”

  • It may be worth noting that the Pike River coal is not burned to make power. It is used to provide the carbon that gets added to iron to make steel.

    With respect to the comment “We prefer the idea of “precision” or “surgical” mining, that operates mostly underground, with minimal impact on the surrounding environment” , it is precisely because Pike River is being mined this way that the methane gas that always accompanies coal is able to build up and cause explosions. Methane isn’t an issue with open cast mining in the same way because the coal is open to the atmosphere. For myself, I would prefer we do open-cast mining at the cost of a scar on the landscape for a century or so before it gets tidied up again, rather than risk another 29 lives – subject to not using coal mined this way for power generation.

  • The coal seam at Pike River is 200 metres underground. Open cast mining was never an option and Peter Whittall has said exactly that.

    This accident has nothing to do with DoC’s protection of the surface environment and everything to do with weak safety standards. An explosive concentration of methane is easily detectable and no company should put its staff into such an atmosphere.

    • @ Jez: Well put. I would like to add that “weak safety standards” can come about in a number of ways. Is the industry poorly regulated in New Zealand? Did the mine operator not adhere to safety standards? Or, did the mine operator simply not instill a “safety first” ethic to those workers? I hope that the inquiry into the Pike River Coal disaster will answer those questions, and make mining safer in the future.

  • Lies, damned lies, and statistics….
    As Possum said, open-cast mining has a different risk profile to the precision mining that is common in New Zealand. What do the statistics for Australia and the US look like if you exclude open-cast mines from the equation? I’m not sure, but I think the numbers would be a lot closer than your figures suggest.

    • @AaronM: You’re probably right. Oz and the US likely have a higher proportion of open-cast coal mines, which may explain the higher numbers of accidents in New Zealand coal mines. Which is exactly why I decided to write this blog. I want people to ask the question “just because we want precision mining in New Zealand, does that mean that we should accept a higher death toll from underground mining”? Unfortunately the stats that I could find dont’ differentiate between surface and underground mining fatalities. I did the best that I could with the limited data that is available.

  • I read your article in the NZ herald.
    I just have to say Jesse, that despite your laymans discussions on coalmining and its processes ( I would have expected a more erudit discussion) you do not know what it is like in a mine.
    I have worked at depths in mines in Australia twice that of Pike River and I know what it is like first hand.
    I have done a lot of study in Geology and petrochemical processes as well.
    Coal mines in general in Australia are largely open-cut mines (cast is a stupid American term to be different in language as is their way) and Australia has vast reserves of Lignite coal at Leigh Creek etc.
    Anthracite coal used in coking processes are found in pockets on the Eastern Seaboard in the Illawarra and Gladstone,Blair Athol etc.
    We have very gasseous coal mines which have been dealt with by effective maintenance and safety procedures.
    Pike River was a disaster waiting to happen.It seems poorly managed and ventilated and the miners commented on conditions in the mine.Relief pipes were 100mm and not at least 300mm to relieve CO2 and CMM buildups.
    There seems to me a lack of circulatory ability to provide the correct egress of harmful gasses from the mine.
    From all the information I have been given, it was a dead end mine a tunnel to a ballroom, with inadequate safety measures and no evacuation tunnel (despite the management saying they were going to build one later).
    Miners leaving the shift that morning said there was a problem with gas and one said it was too dangerous and wanted a transfer etc etc etc.
    All these little jigsaw puzzle pieces fit together into a bigger picture that will ultimately be revealed.
    my Father worked in mines in the Ukraine and one day 300 went down, there was an explosion, and only 17 made it out.
    They only did so as the rescue teams went in 2 hours after the event.
    He was nearly 600 metres underground and 1.5 km from the shaft.
    I think that Pike River (with the unstable Hawera Fault zone) is a mine that should have been approached another way.
    A seismic event will cause a reverse strike-slip and close the tunnel for good one day.

    • @MIM: thanks for your comments. I’d rather not speculate on whether or not Pike River was a “disaster waiting to happen”. As you say, the bigger picture will eventually come to light. Also, while I can’t speak to the role of the Hawera fault zone in this disaster, I would like to add that most mines in New Zealand are potentially subject to earthquake shaking, whether they be open-cut, or underground. A great earthquake on the Alpine/Marlborough/Wellington Fault systems, or the Hikurangi or Puysuger subduction zones is something that will almost certainly happen in the not-too-distant future.

  • Thanks to those who pointed out that China has eclipsed the US as the world’s largest contributor of greenhouse gases

  • Jesse,
    Pike River has issues with its construction in creating a 2km tunnel to get to the deposits through the Hawera fault.
    If you look at the geomorphology of the mine in its relation to the cross-section of the Paparoa Ranges and Tunnel Alignment at Pike River, you can understand what I am saying in my prior statement on a seismic event to the fault zone.
    You need to spend a few months underground to appreciate geomorphology (and its processes and how things react from circumstances and its environment )and a gained a learned practical geological knowledge as I have.
    Evaluation from experience is a very important thing.
    Torsional stresses and various directed pressure on rock morphologies alter so many variables, especially a non-static environment like a coal-mine.
    I wonder if Pike River used CMPG software by Luna Gas , to evaluate changes in the working environment?
    Desorption rates are critical in a coal-mine to monitor and void monitoring as well as goaf monitoring need to be addressed to prevent CMM from reaching explosive saturation levels.
    These websites may help you in your understandings.
    I do use them a lot as I am still involved in mining to a degree.
    http://www.minematters.riotintocoalaustralia.com.au/ENG/articles/search_our_articles_1087.asp

    http://www.miningaustralia.com.au/tags/-mine-ohs

    thankyou for your time and prior comments
    cheers

  • Having been involved in the coal mining industry some years ago in SE Kentucky I would like to comment on this,though not without risk, mining with proper safeguards and assessments preformed can be safe, raping the landscape to get the coal would be a bad idea they have done this in SE Kentucky and it will take decades for it grow back as it was before.

  • Jesse,
    as you say “Coal is the most abundant fossil fuel on earth, with an estimated 900 billion tons of recoverable reserves”.
    What happens if this coal is recovered and converted to energy and carbon dioxide? I have done this back-of-the-envelope calculation. Happy to have any errors in my arithmetic pointed out.
    Hansen’s ‘Target Atmosphere CO2’ paper notes an average of 56% of annual CO2 emissions remain in the atmosphere.
    The Carbon Dioxide Information Analysis Center notes that it takes 2.13 Gigatonnes of carbon emissions to increase the volume of atmospheric CO2 by 1 ppm.
    So, 900 Gigatonnes carbon x 0.56 / 2.13 = 237 ppm atmospheric CO2.

    The additional 237ppm plus the present concentration of 390ppm = 627 ppm of atmospheric CO2.

    Never mind the other GHGs, its pretty clear that using the coal reserves guarantees atmospheric carbon dioxide concentrations that will lead to increases in long-term average temperatures well in excess of the “no more than 2 degrees” espoused by the IPCC and the EU.

  • The use of sophisticated software systems for coal mining (thermal coal, steam coal and metallurgical coal) that is mostly burnt for power generation and steel production and adds to the greenhouse effect is valid for western countries who may allocate resources and funds to alternative and more greener sources of power. Some of the alternatives may be “safer” than the traditional mines. Unfortunately, coal reports and coal statistics show developing economies are more likely to increase their use of thermal coal & metallurgical coal in coming years because of its affordability and to meet increasing demands for electricity and steel. Whether they will embrace and utilise sophisticated software systems that no doubt add to the cost of production is yet to be seen. Ian http://www.coalportal.com