Wednesday, April 28, 2010

British future energy supply - some problems with the numbers

As I travel around the UK there are the odd sign of the coming General Election. Relative to the activities that one would see in the USA they are, however, indeed relatively muted, and the signs, even on the motorway, are no larger or long lasting than those that have, on occasion, decorated our front yard. But with the slurring remark about a voter by the current Prime Minister the entire MSM has become convulsed about the story. Having, in my distant youth, worn a live mike to the bathroom, I am entirely sympathetic with the poor politician, though he should be experienced enough to know better. But it does drive items, of what are really more important news, much deeper into the papers.

Even without that issue taking the space it now does, I had to meander back to page 40 to catch what should be, in reality, a much greater concern for the British public.
Britain could be forced to close 14 power stations if a proposed European directive becomes law, a move that would drastically cut power supplies and endanger energy security, the Confederation of British Industry has warned.
The timeframe is 2016, and the issue is to do with compliance with EU regulations on power station emissions, or closure. Those arguing for compliance with the anticipated regulation see no real problem, and expect the demand can be made up with supply from renewable sources. As a Greenpeace spokesman noted:
"Britain is gearing up for a six-fold increase in the amount of energy we get from clean sources in the next decade, so these CBI scare stories show that the French and German energy monopolies they represent are now seriously worried that the clean tech industry will effectively squeeze out dirty coal power in this country."
And here, of course is the rub. The CBI would have you believe that a quarter of the UK's electric generating capacity is threatened. While GreenPeace argues that increasing renewables negates the concern.

For a little check on these statements the UK Department of Energy and Climate Change (DECC) has issued projections for the generation mix that the UK can anticipate in coming years. Clicking through on Table D, the generation mix table, one finds:

Source Dept of Energy and Climate Change)

There are a couple of things that become obvious from this table. Firstly the current UK Government recognize and buy into the need to reduce overall current traditional power sources. There is the recognized roughly 25% reduction on coal power use (note that by 2017 it is too early to expect any impact from CCS). However it is also remarkable that the supply of natural gas to be used in power stations is anticipated to rise 42% by 2017, something which neither of these two debaters have brough to public attention. At the same time nuclear power generation is anticipated to drop by almost 50%, while renewables only increase by 46%, which is a whole lot less than the 600% that Greenpeace is stating.

The primary question becomes one as to whether or not the UK will be able to get enough natural gas to meet its demands and keep the pressure off renewables. At present there is a lot of complacency, given in part by agreements with Qatar over the supply of LNG. The agreement with Qatar will supply, though the Milford Haven terminal, some 20% of the UK need , which will then be re-gasified and fed into the national grid. But 20% of the national need still requires that the other 80% come from somewhere, since the volume will not even cover the rise in demand to meet the DECC projections.

One of the things I did today was to visit the Lancaster Maritime Museum (in the UK), and they have an exhibition on the gas that comes to the UK from off the coast here. Because of that supply natural gas has been the greatest supplier of energy to the county. In 2006, the latest year with figures available, the supply was for 13,669 GWh of natural gas, 12,545 GWh of petroleum products, 585 GWh of coal and 423 GWh of renewables. (no nuclear). Since 2006 the supply had grown relative to UK demand, now supplying 10% of the national need at a level that is expected to be sustainable for 40 years. What I found interesting was that this NG was coal based, rather than the conventional petroleum (i.e. algae) based origin of the majority of the natural gas in the North Sea. But that is still only 10%.

Now Rune, Euan not to mention Jerome and Rembrandt have posted regularly on the problems that Europe is going to face on natural gas supply. The doubts about the Russian ability to get Yamal and Shtokman into production on time continue. At present Shtokman is being pushed further back while Yamal is given greater priority. The Stern Report quoted the 2007 Gazprom report in seeing a steady increase in Russian supply.

Anticipated future Russian natural gas production.

But notice where the majority of the gas will have to come from after this year - Yamal. And is the investment being made to produce that gas, and won’t an increasing percentage be consumed by the growing Russian economy? There have been some questions over this past year as to whether the necessary investment has been made. And if not, given the quantities of Turkmen gas, and that of other adjacent states that may be heading to China rather than Europe, then additional supplies might not be available in a timely manner.

Which brings us back to the overall question. If there is not enough importable supply of natural gas to offset the decline in nuclear and coal –fired electric power production, then the increase in renewable energy sources that the British Government (as opposed to Greenpeace) anticipate will not be sufficient to meet the demand for power, within the likely term (if normal) of the next Parliament.

There is a widespread pessimistic anticipation in the UK, that the first thing that any new Government, regardless of party, will have to do is to carry out a drastic budget cut. With those cuts, and the lack of investment that they will also likely mandate, then that little page 40 story might get enough legs to move to page 1 before too awful long.

Oh, and why am I in Lancaster – well here is a 53-year old photo that might help explain it. And that may feed into another post, but we’ll just have to see about that.

Smithy House, St. John's Town of Dalry, 1956/7?

It has to do with the school uniform of the kid on the right.

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Tuesday, April 27, 2010

Wind over St John's Town of Dalry

There was, a few years ago, some controversy in the South West of Scotland, over the location of a wind farm in the region. It was to be placed about five miles East of the small village of St John’s Town of Dalry, which, apart from being judged one of the prettiest villages in the British Isles at one time was where, from about 1900 to 1940 my great grandfather, and then my grandfather worked as the village blacksmith. One of the great concerns, as always, was with the disruption that this would bring to the landscape. Another was the risk to the local bird-life since this is the land of the Golden Eagle, and is where kites have been recently re-introduced and are flourishing.

The last time I came to these parts I helped get one of the site staff get to the site, but she left the car before we got there, so I didn’t know where it was. Today we decided to find it. No problem, right? We knew where the land permits were, we had driven past placarded houses demanding “No Wind Turbines”, so I “knew” where it was. So off we drove. We left the main highway (not that large – this is after all rural Scotland) and drove in the general direction of where I was sure it was, skirting roughly the Eastern boundary of the site. A mile passed, then another, moss appeared in the middle of the road. Had I been fooled, or had the recession killed the project?

Are ye lost?

We drove on, guessing that the cones on top of some of the hills were perhaps the foundations for pylons. And on we drove, and then in an instance, as we rode high up on the moors, in the far distance, appearing suddenly in a gap in the hills, there were about a dozen rotating turbines. (The view was not that good). But the road we were on was remote, and (as you may gather) rarely travelled. So we were sure we could get closer for a better view. The road started to descend, and before we knew where we were we were in the valley that carries the road from Dalry to Moniaive. (This is Burns country and Moniaive was where Annie Laurie lived) It was also where I had thought the Northern boundary of the permitted property was – but I was visibly wrong. (As soon as we had started to descend we had lost site of the turbines). So we turned back along the valley, driving to where there had to be an access road. We did find one, but the driver would not take the car up that gravel road, and so we pressed on. We came to a sign for a road to Lochinvar, which seemed to point in the right direction.

To those of you with a romantic heart, Lochinvar was the young swain who rode out of the West in the Walter Scott poem of the same name. This was that Lochinvar, and the castle to which he brought his damsel (an early version of “The Graduate” in theme). Sadly it was flooded by the local entities that needed a water supply, and so there is naught there now but a rather still and quiet loch as we drove by. But still until we almost reached the loch, no sign of the turbines. But then again, for just a short spell and in the far distance, there were the turning turbines.

View of the turbines.

As you can see they are rather hard to discern, and it is only with an “electronic” zoom that you can make out more details

Zoomed in Closeup of the turbines from above Lochinvar

Too soon, however, we were at the loch, and descending into another valley. And so we drove on, meandering up any road that looked even vaguely drivable (i.e. tarred) in the direction that took us closer to where we thought the turbines were, until we reached the high Cairsphairn road back into Dalry. No more sign of a turbine anywhere.

However, in putting together this post, I did come across the overall plan for the total farm, and what we found was part of the farm, we think either that at Margree or at Wether Hill, which was opened in 2007. Having driven along the future sites for the Blackcraig stage, I am not sure how visible they will be. But with the roads only in the valleys, none of the sites was easily seen.

Location of the Turbines (Glare)

The net conclusion, those who said that the turbines would be invisible were about right. With a concerted effort we only twice, and on remote roads, were able to spot them, and short of driving up the installation road (good gravel, but not quite good enough to risk the car on) inaccessible.

The other thing that is available here, though specifically as I recall from earlier debates, is hydro. In and around Dalry lies the Galloway Hydro-electric Power Scheme. Not the great high dams, but nevertheless productive water barriers that can, on demand, produce power from Clatteringhsaws, Lock Ken and Loch Doon. These supply water to the power stations of Carsfad (12 MW), Drumjohn (2.25 MW), Earlstoun (14 MW) Glenlee (24 MW) Kendoon (24 MW) and Tongland (33 MW). At the moment they are not set to provide backup power to the turbines, but they certainly could.

And so, with respect Jerome, hat tip to your industry, they appear to have well fulfilled the initial promise of inconspicuously providing the power that this part of the country needs (albeit it also has coal, but we won’t go there today). Nowhere near the visibility of the first turbines I saw in the UK, and probably a lot more productive.

UPDATE: With a little more checking (having internet problems again) it turns out that the Blackcraig site is still in development there has been a scoping opinion, and that the map above has the earlier sites misnamed. The site in the middle is actually Cornharrow Hill, which with the Wether Hill site was the eighth operational wind farm in Scotland. The site that they show as Wether Hill is, I believe that of the Windy Standard wind farm.

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Sunday, April 25, 2010

Manually mining coal underground

Since last I wrote I have travelled to London and then up North into southern Scotland (I write this looking down at the station in Dumfries, having passed the one-time house of Scotland’s Bard). Today I would like to continue writing on some of the historic methods of mining coal, in part because, in certain parts of the world, this is still the way it is done.

Last time I had talked a little about how mining started where the coal seam came to the surface, or outcropped, and that miners worked their way into the hillside digging the coal out creating both a passage deeper into the seam, and also leaving some pillars, as they widened out the passage way to mine more of the coal. Other times, as the coal became deeper, instead of working from the outcrop, they would sink a small shaft, and mine coal out from around its walls. Because the mines thus had the narrow shaft and then widened in the coal seam they became known as bell pits. They were used in parts of Northumberland as late as World War 1. The miner would break out the coal with a pick, and hand load it into baskets, or corves, that would then, initially be carried up the ladder by children or women. However as the mine got deeper the ladder haulage would be replaced by a hand-turned winch, or later and for deeper mines, a horse gin or other winching system using an animal.

Picture of bell pit

Picture of horse gin
A two-horse gin is reported to have been able to raise some 2.5 tons of coal an hour.

As demand grew, so the underground mining pattern would grow with it. This may was from the Kehley’s Run Mine in Shenandoah, PA. The plan shows how, from the original drift into the side of the hill, the mine spread out along and behind the outcrop, leaving as small a pillar as possible to hold the roof up.

Partial plan of Kehley’s Run Colliery at the time of an underground fire in 1880. The red areas show roof falls. The cracked black are broken pillars, while solid black are pillars with some strength and integrity. (I have cleaned the image a little with Photoshop)

You can see in the illustration how the mine (the current entry is at M, the earlier entry having been closed by the roof collapse shown) mined as much coal as possible to leave the least amount of coal, and that this could cause roof falls. I mentioned one of the fires at the mine, but this mine also raised attention from one of the many riots that erupted between miners, mine owners and their security guards.

Some of these stories have been dramatized in movies such as the “Mollie Maguires”, but it was a grim and vicious set of confrontations based on grim working conditions. In one seven year period some 566 miners were killed and 1,665 were injured in Schuylkill County, PA alone.

Confrontation at the Kayley's Run colliery 1888 (after Popalis )

You might be able to get some sense of the grim conditions from the mine plan. Conditions had been worse in Europe. There are a number of nasty things that can happen in coal mines. As we recently saw and heard, one of them relates to the gas that is given off during mining. Like natural gas from other sources, in ranges from 5 – 15% this methane can be explosive and thus the levels of gas must be kept below this level (hopefully below 1%) if the miner is to be safe.

The other gas that had to be watched for was carbon dioxide, which in contrast with methane, which being lighter than air collects in the roof, is heavier and thus pools on the floor. So that if you were getting down to cut the starting slot in the bottom of the coal seam, you might just drop into a pool. It was called choke damp – though that was also the name given to carbon monoxide, which could also seep out of the coal. All these gases are colorless and odorless so that without some form of detection (the canary for example, or using a candle as a test) they can lurk to catch the unsuspecting. With the invention of the safety lamp (where the heat of the flame is removed by a surrounding mesh of copper wire) it became possible to use the lamp itself as a testing tool. One of my first mining tests was to make sure that I could tell, by the height and shape of the small blue flame of the methane burning over the lowered flame in the lamp, what the gas concentration was. (Each lamp was in a separate hood, and I remember that they had two at the same concentration in the set of around half-a-dozen I had to evaluate).

Methane caps on a safety lamp flame (Colliery Deputy’s Handbook)

When the miner saw the flame cone, he would first wave a shirt or towel to stir the methane into the air, hoping that the concentration would fall below 1%, but if the level built up, he might have to leave, or call for more drastic measures to get rid of it. Back in Medieval times there was an individual called The Penitent, who would wrap himself in wet rags and crawl into the mine with a candle on a long stick. Raising the candle to the roof, he would ignite the layers of methane that would gather there, before the rest of the miners came back into the working. Methane, being lighter than air would gather in the roof, when the air currents were not strong enough to mix it into the air and remove it.

The Penitent – an etching by Hildebrand

But, as they mined coal from further away from the shaft, the air would not easily move around the workings, and since the coal would give off other gasses, as well as methane, there needed to be some way of circulating the air. And so the miners began to run sets of tunnels out into the coal that ran parallel to one another, but with cross tunnels (cross-cuts) between them so that they could circulate air around and up to the working area.

For many years, starting in around 1810 the motive power for the air was created by having a fire in the bottom of the shaft, in a special furnace room. Usually these were underground, although there was the occasional one at the surface. Unfortunately if the fire ignited the surrounding timber that was being used for support, then a major fire could result, killing everyone underground. This was the case with the Avondale mine disaster in 1869, at the time the worst industrial accident in American history, 110 people died.

At first there was only one shaft or tunnel leading in and out of the workings, but a major accident occurred at New Hartley in Northumberland, UK in 1862 where the main beam for the dewatering pump fell into the shaft, blocking it. The 199 men and boys in the mine, virtually the entire working male population of the village, were all killed, It was a result of those deaths that legislation was passed that required that there be two separate ways to get out of a mine. Where the mine is deep underground this means that there are generally two shafts, or more from the workings to the surface. (My Dad was manager at the resurrected mine, and the village school was the first primary school that I went to).

Initially men broke the coal from the solid with picks. To mine more efficiently they would first swing the pick along the bottom edge of the coal, and cut a slot that would be perhaps a couple of feet deep. Then they would drive the pick into the cracks in the main seam section and break the coal to the edge that they had created. When they worked this efficiently, a man can be very effective in breaking out the coal (about 4 joules/cc specific energy, for those that are interested, The machines mine at around 1,000 joules/cc of coal removed).

As the working face grew away from the shaft, it became too slow to rely on women and children to carry the baskets, on their backs, to the shaft and up out of the mine. ( A woman was reported to be able to carry about 56 lb of coal at a time. So first rails were used to slide the baskets along. Then wheels were added, first to flats, and then to small tubs. At first these were of wood, but then were changed to metal.

Although there are still parts of the world where this type of primitive mining still occurs, and where women and children are used to help get the coal out, in most countries they have been banned from underground work. (This was the Act of 1842 in the United Kingdom) . Taking the coal from the miner or hewer to the shaft was known as putting or hurrying. (I learned it as putting).
Six year old girl:
"I have been down six weeks and make 10 to 14 rakes a day; I carry a full 56 lbs. of coal in a wooden bucket. I work with sister Jesse and mother. It is dark the time we go."

Jane Peacock Watson.
"I have wrought in the bowels of the earth 33 years. I have been married 23 years and had nine children, six are alive and three died of typhus a few years since. Have had two dead born. Horse-work ruins the women; it crushes their haunches, bends their ankles and makes them old women at 40. "

Maria Gooder
"I hurry for a man with my sister Anne who is going 18. He is good to us. I don't like being in the pit. I am tired and afraid. I go at 4:30 after having porridge for breakfast. I start hurrying at 5. We have dinner at noon. We have dry bread and nothing else. There is water in the pit but we don't sup it. "

With time horses (or pit ponies as they were called) were taken underground and used to haul the tubs. Ponies were used for haulage well into my working career, and leading one was the first underground job that I had, when I worked in the mines before going to college. They served two purposes, being used firstly to haul the coal from the face, but also to haul wood back to the working area, where the miner would cut the wooden props to length and then wedge them against the roof to hold it up while he worked under it.

Because of low cost, the tubs had very crude axles, and so, to go around a turn, one had first to stop the pony, then switch the points on the rail, then start the pony round the turn, then run back to the back end of the tub, and manually twist the tub so that the axles turned to align with the turn. Fail to do any one of those and the tub came off the rails, meaning you had to unload it, put it back on the rails, and then reload it – all the while with the pony standing there enjoying the break.

Because a man with a pick is, though efficient, quite slow, machines were developed where a large number of picks were set into a chain, rather like a large chain saw, and this was used to undercut the coal seam about a hundred years ago. Then holes were drilled into the coal above the slot, filled with a stick of dynamite, and the blast would break the coal into pieces, that the miner could load into tubs. Typically he might load some 20 tubs in a shift, and these were hauled out of the working area by one of the lads, who would then attach those from several of the faces, and pull the resulting train to the shaft using a pony.

He would put his “token” in the tub before he would fill it, and so, when the tub was emptied at the surface, he would be given credit for that coal, providing it did not have much stone in the pile.

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Wednesday, April 21, 2010

Some hopefully closing thoughts for now on Icelandic volcanoes

The re-opening of the European skies means, among other things, a couple of days of quiet here at Bit Tooth, as I have now left home on a somewhat circuitous trip to the UK. Hopefully I will arrive on Saturday morning, by which time a lot of the major disruption should be over. Public debate will likely now center on who was to blame and for what.

However as a follow-up to my earlier post on aircraft damage and the damage to fighters in particular, I do note that there are reports of two aircraft already having been damaged following the removal of the ban on flying, (H/t Admiral Valdemar) and that after Pinatubo erupted, aircraft damage was found in over 20 planes flying up to 1,000 km distant from the volcano.

This is probably, barring a major change in Iceland, my last post on this topic for a while – I expect that it won’t come up again for about a year until there is an eruption at Katla or Laki, potentially about ten times the size of the current event, and that the whole issue will come back into the headlines. So I thought I would explain why I think that there will still be an eruption further along the rift line, and how, simplistically why I expect this to happen. Call it a summary of the posts to date if you will.

Let me walk you through my thinking. Iceland sits on the spot where the plates that comprise the shell of the Earth, are slowly moving apart. The plate edges are marked in pink, and by the line of volcanoes, in this graphic.

Map of Iceland showing major volcanoes (The Times of London)

If you look at the Icelandic Met Office website, they show, every two minutes, where the latest earthquakes in Iceland have occurred over the past two days. Looking at the current picture, one can locate the earthquakes relative to the joint plane and the line of volcanoes.

Note that if you double click on the map it will enlarge – vide:

Area around Eyjafyallajokull, showing the current earthquakes there

It is not however Eyjafyallajokul that has my interest. Let me try and explain why. The two plates which lie either side of the line of volcanoes are moving apart at a rate of about an inch a year. As theplates move apart they pull on the rock that sits between them, so that it splits and cracks, and emits the energy release from that fracture that we call an earthquake. As the splits grow they create a weakness plane along the fault line. Under the fracture zone there is a magma that will force its way to the surface, when it finds a weakness of fracture plane that is large enough to start the magma flow.

Once the magma starts to flow it will open the fissure under pressure, and erode the walls of the passage until you get the standard round shape for the conduit that carries magma to the caldera where it is ejected. But the pressure of the flow also helps push the rock apart, and in the process can open adjacent passages in the rock under tension, allowing a secondary flow to establish. That will likely lead, within a year of so, to the more dramatic eruption of Katla, which sits under the Myrdalsjokull glacier.

But there has been a lot of activity up around the north end of the larger glacier near the peak called Grimsfjatt. This is sometimes referred to as the Loki volcano. And this may be creating the circumstances for a rupture that will equate to that of Laki, which is currently quiescent.

But stepping back a minute to look at the overall activities that occur when plates interact, what has been learned in places such as California, is that when the plates are moving together and not building up stress, then there are always a series of small earthquakes going on along the fault, as the ground accommodates the movement.

California quakes of the last two days

It is only when the earthquakes stop happening in a region that the stresses start to build up. And the longer there is between quakes, then generally the larger the quake is that marks the end of the quiescent period.

But those are compression/shear failures and movements. In Iceland the rock is moving apart under tension, with the added complexity of an underlying magma trying to escape through preferred fracture zones. Yet looking at the current location of the quakes in Iceland, there haven’t been any in the zone between Myrdalsjokull and Vatnajokull. Now a) this is where Laki lies and b) having been only watching for just over a week, this may be building large sand castles out of very dry sand, but nevertheless it is a little bit of a puzzler, and so, based on three different thought threads, I suspect that while the current eruption may rumble on for a while, and fade rapidly from the MSM, sometime within the next 18-months Iceland will be back in the headlines, posing a much greater problem for Europe.

Having said which, I’m still optimistic about getting into London this weekend, we shall see how it transpires.

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Tuesday, April 20, 2010

Winds, plumes, travel and the Iceland volcano is not predictable

Following an increase in the ash clouds generated by the volcano at Eyjafjallajokull NATS has issued the following statement for today:
The situation regarding the volcanic eruption in Iceland remains dynamic and the latest information from the Met Office shows that the situation today will continue to be variable.

Based on the latest Met Office information, part of Scottish airspace including Aberdeen, Inverness and Edinburgh airports will continue to be available from 1300-1900 today, and also south to Newcastle Airport. Restrictions will remain in place over the rest of UK airspace below 20,000ft.

Overnight the CAA, in line with new guidance from the International Civil Aviation Organisation (ICAO) decided flights above the ash cloud will be permitted in the UK; between 1300-1900 this will enable aircraft movements above 20,000ft in UK airspace.
The Met Office, whose models of the ash cloud have come under criticism has responded by noting
The Met Office uses multiple dispersion models endorsed by the international meteorological community. The output from the Met Office volcanic ash dispersion model has been compared with our neighbouring VAACs in Canada and France since the beginning of this incident and the results are consistent.

Our models are confirmed by observations which have seen ash in the UK and south of England. These include:
• Met Office and NERC aircraft have observed volcanic ash in UK airspace at varying heights.
• Multiple land observations have recorded ash in the skies across the UK, including across southern Britain.
• Balloon observations have shown a 600 m deep ash cloud at an altitude of 4 km across parts of the UK.

NATO F16 fighter jets have reported engine damage, due to volcanic ash when flying through European airspace.
And given that there is some blame now being tossed around the main stream media, as well as some blogs, on who made what decision they go on to point out
It is for the aviation industry and regulator to set thresholds for safe ash ingestion. Currently, world-wide advice from ICAO is based on engine and airframe manufacturers stating a zero tolerance to ash ingestion. This means that aircraft should not be exposed to any volcanic ash.

Eurocontrol is trying to get this restriction eased, with the support of some airlines to:
A proposal by Eurocontrol, the intergovernmental air traffic body, to European transport ministers suggested the implementation of a no-fly zone limited to the visible ash plume as determined by satellite images and adequate buffer areas which could be updated on a six-hour basis.

The current map of the ash that the Met Office has produced shows that there is a way of getting from the US to the UK without going through the cloud, but only as far south as Newcastle. There are moves to do a better job on predicting where these flight paths would be. While planes can now fly over the UK, it is getting down through the space below 20,000 ft that contains the ash that is the problem, and you have to do that if you are landing or taking off.

But it also shows how the ash has put a barrier between Northern and Southern Europe.

After the height of the cloud being produced had reduced over the past few days, there was hope that it was not getting high enough into the atmosphere to reach Europe (i.e. below 3 miles). The latest outburst, however, put more material higher into the atmosphere strengthening the cloud once more.

I wrote yesterday about the size of the particles, and why those that are in the 50 – 100 micron range are particularly dangerous as abrasive cutting threats to aircraft. Smaller particle sizes, around 5 microns, are the greater personal threat, since these very small yet sharp particles can be breathed into the lungs and do damage, both chemically and mechanically. Larger particles fall out of the cloud fairly rapidly but the smaller particles, which are formed both from the contact of the molten lava with water and ice (which causes it to shatter) and from the bursting of bubbles of gas that are being emitted within the molten rock, and burst as it reaches the surface, are the ones carried higher both by the relative heat of the plume, but also by the prevailing winds.

Part of the problem that is sustaining the cloud has been the warm weather with a fairly steady wind direction although this is swinging south, with the predictions through Friday suggesting that the cloud may intensify while narrowing. There is some hope that an increase in wind speed could displace and disperse the ash already over parts of Europe confining the restricted zones (which sadly seem likely to include the airports of the south of England) to a narrower band. The projected path of the wind does seem to vary with forecasters, this is from Accuweather, which has the cloud sweeping back north over Scotland, and moving away from the southern airports, while the Met Office view (above) has the cloud further South and covering them.

Projected Ash Cloud path (Accuweather)

Winds at the level of the ash plume are also expected to become more aligned Tuesday into Wednesday, which may result in the ash plume becoming more concentrated and posing a greater threat to air travel. This, of course, is assuming the volcano continues to erupt through then.

On a positive note, meteorologists expect this greater alignment of the winds to cause the ash plume to become narrower and affect a smaller area.

Looking at American Airlines policy for future travelers, while the notice says:
Due to the ash plume from the volcano that erupted in Iceland, some of American Airlines operations have been disrupted. Ticketed customers whose flights have been cancelled are being re-accommodated on other American Airlines flights with available seats. If a customer whose flight has been cancelled decides to cancel or reschedule their trip instead of continuing travel, that customer is eligible for a refund on any unused portion of their ticket.

In addition, American offers customers whose flights have not been canceled, but who are traveling to or from the impacted areas in the next several days, the convenience to change their plans. Ticketed customers may change flights as shown below, without incurring a charge for changing their tickets.
In essence the “shown below” says that passengers who booked flights before April 16th, and who plan to fly between the 16th (when this started) and the 22nd (Thursday) can change tickets without penalty only if they rebook their flight to occur before May 3rd. Part of the problem with that is of course no-one knows how long this will go on, and in my own case I have to be back here by a certain date, and so am a bit restricted in my options. (Oh, and they only allow one re-booking).

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Monday, April 19, 2010

Some thoughts on aircraft damage from the Iceland volcano

There is increasing pressure on the governments in Europe to allow commercial aircraft flights to resume, because of the financial hardships they are suffering. At the same time the impact from the absence of teachers and students in classes, as they resume after the Easter break, has caused some additional problems around the UK. Unfortunately just having commercial companies take jets up and fly them around for a while, does not necessarily prove that the skies are completely safe. There is also a little discrepancy between the commercial company reports of no damage to their planes, and the damage to a Belgian F-16 plane that came back with deposits in their engines (this is separate from the Finnish F/A-18 problems). The build-up of melted ash can be seen on this borescope picture of the inside of one of the Finnish engines.

The deal that has been developed with break the airspace into three separate parts, that which remains closed, that which is restricted and that which is open, based on the conditions in different zones. The problem now will come in determining and maintaining the records of what the conditions are like along different flight paths, so that pilots and airlines can make the best judgment of how, where and if to fly. The process cannot be left to the pilots since it is very difficult to discern when the particle cloud reaches a level of intensity that can cause problems.

The melting of the ash particles so that they coat the inner parts of the engine, possibly closing off critical openings in the engine are the most common problem that a plane will apparently encounter in a brief exposure to the ash cloud. It is not, however the only problem. A 747, for example, flies at a cruising speed of 567 mph. This converts to 830 ft/sec. At these particle velocities there is an entire commercial industry out there that uses such particles, in a waterjet stream, to cut through a wide range of materials. As an illustration, this is a half-inch thick piece of titanium that one of my graduate students cut using such a system. The jet was travelling across the piece at a speed of several inches a minute, and cutting all the way through (the cut was made fairly slowly to ensure an acceptable surface finish). In steel when running a standard quality test the jet of abrasive, which carries about 0.8 lb of abrasive particles in every gallon of water, will cut to a depth of about 1.75 inches at a cutting speed of 1.5 inches/minute.

Half-inch thick titanium sheet cut through by abrasive slurry jet. (The face visible if that which was exposed by the cut).

If the impact speeds are higher, then it is not necessary to have particles in the water, though that generally requires higher impact velocities. (There is this story about Andy Fyall of the Royal Aircraft Establishment - Farnborough, a Concorde and a typhoon that I don’t seem able to find on the web! But I remember it from an early ELSI conference).

The particles that are used in cutting are quite small (they typically come out of orifices that are smaller than 0.03-inches) but they are quite densely packed in the jet, relative to those encountered in the plume of a volcano, but at high speed it does not take that many to start to do damage. Damage is reduced, however, at particle sizes below 100 microns, (0.1 mm). So the question is, how big are the ash particles? While there is not enough data yet on the current eruption particles, there is some from the eruption at Mt St Helens.

Particle size v travel distance (Sarna-Wojcicki and others, 1981)

The particles that will travel furthest appear to be mostly in the 50 micron and below range, though 100 km from the volcano there will still be 100 micron particles in the cloud that could be significantly damaging. (Respirable particles are down in the 5-micron range).

The question thus remains as to how to tell if the particles are there in sufficient density to cause problems. And so far there is not a lot of consensus it appears on how that determination will be made. The problem also arises in determining at which height the plume is going to be, since the varying intensity of the eruption has been ejecting material to different heights. More recently higher clouds have obscured the plume, on occasion, from satellite view, which is partly because the intensity is, perhaps temporarily perhaps not, decreased.

There are, unfortunately a lot more things that we don't know, as yet, about the eruption, that will only be determined with time. Thus it seems a little better to proceed with caution at this point, until the techniques for establishing what is safe, and what not, have been clearly established.

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European airspace 6:45 am CST

This image showing 128 aircraft in European airspace, would indicate that airlines are beginning to find ways of getting planes into the air. However the patterns show where the plume is still probably too dense to allow flights. Including the UK, where the Government is apparently going to send Navy ships to help.

And just to make you feel comfortable about listening to experts, this was the listing for Europe's ten most dangerous volcanoes (in terms of their impact on Europe) just four days ago:

Volcano . . . . . . . . .Country . . . . . .Affected population . . . Values of residences at risk
(US $billion)
1. Vesuvius . . . . . . . Italy . . . . . . . . 1,651,950 . . . . . . . . . . 66.1
2. Campi Flegrei . . . Italy . . . . . . . . . . 144,144 . . . . . . . . . . .7.8
3. La Soufriere . . . . .Guadeloupe, . . . . .94,037 . . . . . . . . . . . 3.8
Guadeloupe France
4. Etna . . . . . . . . . . . Italy . . . . . . . . . . 70,819 . . . . . . . . . . .. 2.8
5. Agua de Pau . . . . .Azores, . . . . . . . .34,307 . . . . . . . . . . . 1.4
6. Soufriere . . . . . Saint Vincent . . . . . .24,493 . . . . . . . . . . .1.0
Saint Vincent, Caribbean
7. Furnas . . . . . . . Azores, . . . . . . . . . .19,862 . . . . . . . . . . 0.8
8. Sete Cidades . . . Azores, . . . . . . . . . 17,889 . . . . . . . . . . . 0.7
9. Hekla . . . . . . . ..Iceland . . . . . . . . . . 10,024 . . . . . . . . . . .0.4
10. Mt Pelee . . . . .Martinique, . . . . . . .10,002 . . . . . . . . . . 0.4
Hekla is the only one from Iceland that makes the list, which, given that Katla is likely to be perhaps ten times as large as the current eruption from Eyjafjallajokull, and may well go in the next 2 years perhaps underscores the occasional need to question expert opinion.

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Sunday, April 18, 2010

Early mining and transportation of coal

On the 18th April, Ugo Bardi posted a piece on The Oil Drum discussing some of the dark sides of coal mining. In particular he started with one of his favorite paintings “The Riverbank’ by Telemaco Signorini. He ties this picture of men towing a coal barge into a memory of his earlier life. And so, from the other end of that supply chain, that brought coal to Florence, today I am going to talk about the early history of coal, but from the region around Newcastle, and further north up by Alnwick, which is where my coal-mining ancestors came from.

When I saw Ugo’s painting I was immediately reminded of the movie “1612” which has, in a more modern recreation, more than five men hauling a boat.

Towing a boat – from the movie “1612” directed by Vladimir Khotinenko

The commentary that comes with the DVD makes some point of the difficulty in hauling the boat, even though it was relatively small and there are more than twice as many men as Ugo portrayed. It was also unladen.

Though the crew look strong, they are after all actors, and are attached to the boat by a harness of ropes that it likely take more time for them to learn to properly operate than they had for that shoot. (As one of the comments on Ugo’s post noted, this scene could have been taken to reproduce the Russian painter Ilya Repin’s painting “Burlaki” which it emulates).

Ugo also deals more with the political constraints in the coal trade after 1860. Since I am more concerned with discussing reserves and methods of mining and the more technical considerations, I am going to start a little earlier in the use of coal, when it was mined in the UK, and some of the early practices.

When coal was first used, the legends have it that it was collected along the sea coast near Tynemouth in the North-East of England, and taken to the local priory and the rights to the coal were given to the monks. (The scene is illustrated in the movie “Nine Centuries of Coal.” (Which if I understand the BFI rules you can download if you are at a British University or school).

Coal was used to provide the fire for the local lighthouse at Tynemouth until about 150 years ago. The monks did well by their ownership of the coal rights, by 1281 they were shipping the coal down to London where it brought nineteen shillings a chauldron. (There were 20 shillings to a pound, which is currently worth $1.44, though the value has historically been higher). A chauldron was a wagon that would hold around 80,000 cubic inches of coal or just over 45 cu. Ft. of coal, or about 1.7 tons of coal, when it was mined. when it got down to London the measure changed so that while whle, by one definition a chauldron was 36 bushels, but
8 chaldrons at Newcastle, makes at London about 15 chaldron.
The unit was abolished in 1963.

1870 Chauldrons at the Beamish Mining Museum (Terry Pinnegar )

So we know that coal was heading down to London, where King Edward (because the fumes apparently sickened his mother) banned it, with the threat of torture and death to those that used it. (This is the king that had Wllliam Wallace, as played by Mel Gibson in Braveheart, chopped into bits, while alive, so he generally wasn't someone you wanted to mess with). But is was sufficiently cheaper than the wood alternative that the ban had little effect, and coal has been a major fuel in the United Kingdom ever since.

The king, incidentally, was compensated in other ways, since a royal duty was imposed on the mining and shipping of coal, that brought in a large income over the years. In 1818 the mines were estimated to produce 15 million tons a year, for domestic use, with additional amounts used by industry. The duty was 9 shillings and four pence to London, and 6 shillings to other ports in the UK. And this brought in a revenue of 570,066 pounds in 1816. Some 2.25 million chauldrons of coal were shipped, roughly half of which originated in Newcastle. The coal was generally taken by rail, though hauled by horse until the invention of the locomotive (by a local miner), down to the river where equipment known as “drops” were used to swing the chauldron down to the collier for unloading.

The staithes at Wallsend by Hair (1844)

The staithes includes the short pier and feeds to the drop.
At its extremity is fixed the drop, consisting of a square frame hung upon pulleys, and counterbalanced by back weights. The loaded wagon, together with the square frame, descends by its own gravity to the hatchway of the vessel, delivers its coals, and, in turn the empty wagon is returned by means of the balance weights, the motion heing in both cases regulated by a brake wheel. A man is lowered down with the wagon , whose business is to unhasp its moveable bottom, and thereby let the coals drop into the hold of the vessel.
The drop was patented in 1800 by Wm Chapman. A tapered spout led the coal into the hold of smaller keels (the boats used to carry the coal out to larger ships). The main coal mined came from the Bensham and I 1836 93 ships carried some 15,519 tons of this coal through the staithe at Wallsend to London, where it sold for 7s 9d a ton, while one ship carried 318 tons from the Bensham Wallsend, and it sold for 8s 6d a ton. (Personal note – I have worked in the Bensham seam, albeit some 125 years later).

Mining had progressed by that time from the initial collection of loose coal washed up on the beach (sea coal) to mining it where it outcropped, and then mining back into the seam outcrop from the surface, and this often meant that the tunnel that was mined sloped down into the ground. The dirt that was mined out was dumped at the entrance to the tunnel, and often created a small narrow feature on the ground, a tip, some of which can still be seen today. Our family, for example, used to be coal miners at Eglingham. This is a small village found in the North East of England, not that far from the Scottish border.

Aerial view of North of England (Google Earth)

I have marked an overview of the village with a couple of arrows to show where the two tips were that I have walked around (and where my ancestors no doubt worked) on an overall view of the village (using Google Earth) which is at the bottom of the picture. Given the fact that I am going to show you that it was a mining site, it was wryly amusing to see signs in the local parish hall asking for action to protest the location of wind turbines on this "pristine English countryside."

Eglingham (Google Earth)

Right in the center of the picture however, if one zooms in until GE tilts a bit, you can see a third tip quite clearly.

Pit tip at Eglingham (Google Earth)
My aunt (the Teacher) had done some research on where we lived, and this was not down in the current village but up where the top left arrow points, and where all that is left of the houses are circles where the gorse grows, but where rabbit warrens have brought up small pieces of china, and other remnants of the time that folk lived there, only a couple of hundred years ago.

Ruins at Tarry, near Eglingham (55deg 28”55.84” 1deg 49”43.76W)

In those days it was pre-mechanization, and the miners used only a pick and a shovel to break the coal from the solid. It was then put into woven baskets called corves, that were dragged to the surface on a wooden board, either by younger boys, or by women. The board would slide up the tip, and could be dumped before being dragged back underground. The tunnels were driven to the height of the coal, which in the area may have been somewhere around 4 ft 10 inches (with an interbedded layer of stone that ranged from 3 inches to 2 ft thick) or 5 ft 8 inches, (with 3 ft of interbedded stone) not the richest of workings. It was only after some years, and larger mine developments that the baskets went from being carried on folks backs, or on these boards, to being put on flat cars and moved by rail.

Bottom of the shaft, Walbottle Colliery Hair (1844)

Stephenson, who invented the Rocket, the first locomotive as a way of hauling mine chauldrons down to the staithes, began his working career by weaving canes into these corves in a pit yard.

In these small operations, with all the excavation from the initial tunnel into the side of the hill, the coal was mined by individual workers, or families. The miner would work with a candle as a light, and that would be mounted to a wooden post that he would use to hold the roof up.

Undercutting the coal

Laying on his side, he would then take his pick and cut out a slot at the bottom of the coal. This undercut, perhaps 3 ft deep, would be cut along the total face of the coal, before the miner would start to work up. Depending on the size of the tunnel he may also make a vertical cut to create a second free face. (You can see some of these markings in the walls of old stone quarries, and in the mines under Bath in the UK, and the salt mine at Wieliczka in Poland). He would then break out the coal in individual lumps that were several inches in size. (4-6 would be ideal). If he used the joints (called cleat) and the bedding planes of the coal, then this was not too difficult to do, and so he could mine out several chauldron’s worth of coal in a shift. In the measurement of the work he did using a modern measure it would take as little as 4 joules/cc of energy to break out that coal.

Wall at Wielicza, showing the pick patterns used to cut the initial slot to which the rest of the rock would then be broken.

A typical shift would be around 8 hours, but it shrank, so that when I went into the mines it lasted only 7.25 hours. As well as mining the coal, the miner had to hold up the roof, and, if there was a roof fall repair it. But of all his concerns the most prevalent was that of gas. Remember both that he had to breathe, and that coal emits methane, or natural gas, from most seams. The methane will burn, or in the right concentrations in the mine can explode. And when that happens it consumes all the oxygen, so that even if the miners aren’t in an area where the explosion happened then they may still die as the de-oxgenated air circulates underground.

Initially the miners would work only a short distance into the outcrop and though the mining site here was worked at least from the early 1700’s, in the south of England miners had already learned to sink shafts and to mine out from them – but I will get to that next time.

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Saturday, April 17, 2010

Iceland volcanoes and when can I travel?

Yikes! Flightradar has taken out their inclusion of the airports in the overall picture, and the emptiness of the European skies becomes even more apparent.

European skies at 12:48 pm CST

And so the next question comes as to how long will this last? And unfortunately the news there is not particularly encouraging. Even short flights through light ash from this eruption have already been shown to damage aircraft and so authorities are rightly going to be very conservative on what they allow. The backlog on passengers already caught in the cancellations are now up to more than a week.
Honeymooners Paul and Tracy Sheehan, of Kent, England, were among those trapped by the ashy atmosphere.

The couple arrived to catch a transfer flight on Friday night - only to hear the next available American Airlines flight home was one week away.
The hope that the volcano would have settled down enough to allow a scientific flight over the plume has been premature, and the flight was cancelled as the eruption continues.

Given that there is talk of other volcanoes erupting it might also be appropriate to go into a little more depth on the scale of these events. They are measured on a scale known as the Volcanic Explosivity Index (VEI) with values that can be read from this table:
Volcano Explosivity Index (from Rowlett UNC)

The initial measure for Eyjafjallajokull was at a scale of 1, but it hasn’t been possible to assess where it is now fitting. In contrast, as I noted Thursday when Katla last went it was at a scale of 5, and the Mount Pinatubo eruption in 1991 was a 6.

However Pinatubo was a single event eruption, ejecting some 15 – 30 million tons of sulfur dioxide, along with 5.5 cubic km of other material in a nine hour period on June 15th. The consequences lasted much longer.
The eruption plume of Mount Pinatubo's various gases and ash reached high into the atmosphere within two hours of the eruption, attaining an altitude of 34 km (21 miles) high and over 400 km (250 miles) wide. This eruption was the largest disturbance of the stratosphere since the eruption of Krakatau in 1883 (but ten times larger than Mount St. Helens in 1980). The aerosol cloud spread around the earth in two weeks and covered the planet within a year. During 1992 and 1993, the Ozone hole over Antarctica reached an unprecedented size.

The cloud over the earth reduced global temperatures. In 1992 and 1993, the average temperature in the Northern Hemisphere was reduced 0.5 to 0.6°C and the entire planet was cooled 0.4 to 0.5°C. The maximum reduction in global temperature occurred in August 1992 with a reduction of 0.73°C. The eruption is believed to have influenced such events as 1993 floods along the Mississippi river and the drought in the Sahel region of Africa. The United States experienced its third coldest and third wettest summer in 77 years during 1992
Icelandic volcanoes are generally less immediately intense, spread over a longer fissure, and last much longer.

The initial fissure eruption at Eyjafjallajokull (AP)

Katla which is expected to possibly also erupt, last erupted in a major way in 1918, with 25 major eruptions in the last 1200 years. (Which gives an average interval of 48 years). These intervals are likely to continue, on average, given that the two plates that touch under Iceland are moving apart at a speed of around 19 mm/year. While this sounds as though it is a small amount, it puts the rock in tension, which makes it a lot easier for fluid such as magma to penetrate through flaws and fissures in the rock, as these open under that movement. It also helps explain why, on occasion, there is a progression of the eruption up a line, as we are currently seeing with Eyjafjallajokull. And given that there may be volcanic activity at different places, it might help to see where the different volcanic/separation zones are:

The EVZ, fissure swarms, central volcanoes and calderas. H and T denote the Hekla and Torfaj ̈okull central volcanoes. Focal mechanism and location of the 1987 Vatnafj ̈oll earthquake are from Bjarnason and Einarsson [1991].(Jonsson )

The Eastern Volcanic Zone (EVZ) shown above is thought to now be more dominant than the Western one, which has been relatively inactive, and it is here that the current crop of potential eruptive sources sit and that are being worried over. (Hekla for example has erupted in 1970 (VEI 3); 1980 (VEI 3); 1981 (VEI 2); 1991 (VEI 3); and 2000 (VEI 3).

So, given that the last Eyjafjallajokull eruption lasted over a year, and the length of time since the last Katla eruption, and the movement of the plates being relatively consistent, there is not a lot of room for optimism. It may not be an immediate follow-on in the human scale of time, but in geological terms a year later is almost such, so it may well be that the powers in Europe, and around the world, may have to rethink how folks can be moved, if air travel is going to be more of a hit and miss event for a couple of years. So will I get to Europe next week?

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Asphalt highways, gravel roads and the pig manure answer

One of the problems that the rising price of crude has created lies with the related cost of asphalt. As a result states are being more creative in spending their repair budgets, and it is interesting to see some of their answers. Asphalt is used extensively in creating the roads that we drive over every day. Because of this traffic, and movement of the underlying material, roadbeds can fail and erode. But not all do, at least to the extent of the majority. Just this last week the Asphalt Pavement Alliance has announced the winners of this years Perpetual Pavement Award. The winners have to be the owners of asphalt pavements that are at least 35 years old and have never had a structural failure, and the average time between resurfacing has to be no less than 10 years. There are ten awardees, with sections of highway that won being found in Alabama, Arkansas, Kentucky, Michigan, Minnesota, Mississippi, Missouri, Nebraska, South Carolina and Tennessee. The winners range in length up to 12 miles, and from Interstates to State Roads.

Asphalt has been getting more expensive, as the price of crude oil increases, and this reflects back to the state highway departments that must repair damaged roads.

In Illinois, for example, the average asphalt overlay will last between five and eight years (Illinois State Toll Highway Authority) or eight to fifteen years (Illinois Department of Transportation). The decision on repair is a function of both the amount of damage, and the amount of traffic. One consequence of this is the return from asphalt coated to gravel roads. Ugo Bardi recently commented on this at The Oil Drum. He noted that an early use of the Canadian Tar Sands was as a direct application as a roadbed material, and the same has been considered for the West Indies.

Asphalt is one of the most re-circulated of materials, since the material that is laid into the roadbed is only about 5% asphalt and 95% aggregate, so that when the original surface is removed as part of the resurfacing operation, about 80% of it is recycled. And it is not just the aggregate, and some of the binder that gets recycled.

Starting in 1994 Florida DOT has also mandated that the mix include recycled ground tire rubber.
From 1994 through 2007, Florida has recycled the equivalent of over 12.5 million passenger tires into asphalt pavements, saving valuable landfill space while improving the performance of our highways. That works out to over 471 passenger tires per lane mile. Current research shows benefits of combing both ground tire rubber and high tech polymers to improve asphalt binders even more.

Because of the changing price of oil, most states have an adjustment index for the price of asphalt that their construction contractors buy (and then charge the state for).

Some states are returning roads back from asphalt to gravel, though this is not as easy as it may at first appear, since the construction of the roadbeds is different, as is the maintenance, since a gravel road is graded back to quality, rather than being ground up and resurfaced. This is particularly true when road traffic is light, but a number of states are moving this way because of budget constraints.
Thirty-eight counties in Michigan replaced a total of 100 miles of asphalt roads with gravel because of decreasing funds in 2008-09, said Monica Ware, a spokeswoman for the County Road Association of Michigan.

In Montcalm County, Mich., 10 miles were converted to cut patching costs in 2009, said Randy Stearns, managing director of the county's road commission. He cited one road that cost a combined $39,244 in 2008 and early 2009 for patching, but only $7,300 to crush into gravel. More roads may be converted this summer, he said.
The relative costs of going from gravel to asphalt indicates that the transition comes at around 200 vehicles/day.

Relative costs for different road types (U of Minnesota )

Now the price of asphalt is anticipated to rise again, and so what are states to do? In Missouri, a state that grows a lot of pigs, – mainly in farms, though there is a concern over the rising numbers of feral hogs in the state. Putting the problem of disposing of a lot of porcine waste with the high cost of asphalt, folks in Missouri, at the highway leading into Six Flags at Eureka (just outside Saint Louis) have taken the logical next step.
The witnesses lining the bright stretch of North Outer Drive along Interstate 44 — particularly those with noses and an abiding interest in sustainable technology — won't soon forget the moment the red dump truck deposited a 15-ton load of the designer asphalt into a road paver late Wednesday morning.

"Whew!" gasped a worker with Pace Construction Co., the St. Louis County road contractor that joined forces with Innoventor, the Earth City-based engineering and design firm that perfected the process of converting the animal waste into a bio-oil used in asphalt binder.

To others, the air swelled with the sweet smell of potential for new manufacturing opportunities, jobs and, possibly, profits.

The initial stretch of road treated was some 500-ft long, and will get a significant seasonal traffic from the amusement park, accelerating wear potential and allowing the evaluation to be made in a shorter time.

The process was thought up and developed through Innoventor. Essentially the animal waste is converted into a bio-oil that can serve as the binder in the asphalt. The program is currently getting the close attention of the Missouri Department of Transportation, as well as the U.S. EPA. (And I suspect that the next time I drive by the site, I may roll down a window and have a quiet sniff).

It takes all kinds, to find the right answers.

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