Waterjetting 21b - collecting debris, or mined product

You don’t have to operate a water jet lance for any time before realizing that the rebounding water, and the debris from the operation can’t be ignored. On the other hand, after they fall to the floor they rapidly lose their energy and without some additional input will lie in the most inconvenient places until moved. Protection from the rebound is a critical part of the protective clothing and equipment that the operator wears (including side shields for the eye protection) but the collection and removal of the spent material is also critical to good operations, and in uses such as mining it is needed to carry the material to a point where it can be processed.

While this was fairly obvious to those who used water in earlier times to wash out soil and minerals and carry them down to flumes and separation devices, it was not always immediately obvious to those who experimented with the use of larger jets for underground mining. There are two critical velocities involved, once the particles are removed from the surface, these are the settling velocity and the suspension velocities of the particles. Essentially these are the speeds at which the transporting water is travelling that prevents, or encourages, the particles to settle out. This is an important part of drilling horizontal holes, where the drill cuttings can settle in the long hole hehind the drill, and can both stop the drill from moving forwards and also trap it when it tries to retract (personal experience).

Figure 1. Settling velocities (after VCCS)

Because of the wide range of particles that are mined by a jet, it is sometimes suggested that flow velocities in flumes remain above 40 ft/sec. It becomes a lot more difficult to get particles back into suspension after they have settled out.

Because water and debris are dispersed around the impact point after jet impact and because the amount of water needed to keep the particles suspended and moving has to be high, this often means that the geometry of the excavation has to be tailored to capture and confine the water in a narrow space with the mined product.

The National Coal Board carried out early experiments in coal mining in Wales at Trelewis Drift. (Jenkins R.W. “hydraulic Mining – The NCB Installation at Trelewis Drift” MSc Thesis, University of Wales, 1961).

Figure 2. Early NCB remotely operated monitor (after Jenkins ibid).

The 5-ft 6-inch thick seam dipped at roughly 6 degrees, and the monitor was used initially to drive the drift, and then to slab off coal from the pillars on either side, and then to mine along the face of a pillar, driving coal from one drift to the next adjacent, as the drift was retreated.

Part of the problem that arose was that the coal broke off in pieces that were up to 2-ft thick, and once these fell to the floor they became more difficult to recover, particularly where they were scattered (and this was the reason that the monitor was being operated remotely since the debris was reaching the miners). (Jet pressure was around 1,000 psi). The mine was naturally very wet (over the waders of some miners) and production did not exceed 45 tons a shift, even though the costs at the time were around 50-pence per ton in 1963. The conclusion was that the slope of the seam was not adequate to help enough with coal transport and the experiments were terminated.

This is in contrast to work elsewhere (the British trials had been commissioned after Russian hydraulic mining trials had been reported as successful). But the Russian work was carried out in the Donets coal basin, where the seams are much steeper, and more difficult to mine conventionally.

V.S. Muchnick wrote his dissertation on hydraulic coal mining in 1935, describing these early trials. While it was difficult to manually work in the steep seams, setting up a simple monitor that would wash away the coal, which would then fall under gravity to the drift tunnel beneath the mining operation was much more successful.

Figure 3. Early Russian Monitor (RGM-1)

Because of the Second World War hydraulic mining did not get its start until 1952 at the Tyrganskii-Uklony mine in the Kuznetsk Basin. Production in the hydraulic sections was anticipated to be 500 tons.shift, but by the end of the first year it had already exceeded 600 tons, more than twice conventional mining production. In the early operations the coal was weakened by blasting, but by 1957 jet pressures were raised sufficiently that this was no longer needed.

Figure 4. Showing the major Russian coal basins (Gazprom )

By 1979 there were nine major hydraulic mines in the Soviet Union with an annual production of over 8.9 million tonnes. As the mining operations expanded, so the monitors were increasingly operated remotely using hydraulic cylinders to direct the jets at the coal. At pressures of 1,500 psi the monitors could mine over 50 tonnes an hour, using around 650 gpm of water. (This was later doubled).

In almost all these operations the mine is worked in retreat, first driving the drifts to the back of the section, and then mining back, allowing the coal either to fall into the drift, where the water volume is sufficient to carry it into the flume, or pushing it down to the underlying drift, where it can similarly be collected.

Figure 5. GMDTs-3M monitor used in the Soviet Union

The mining pattern changed with the thickness of the coal, and with the steepness of the slopes at which the seams ran, although the access drifts were run more up dip, while the mining drifts were at a shallower angle closer to horizontal, so as to make working conditions easier, and to more effectively remove most of the coal from the section. In this way the coal collapsed under gravity down to the drift, where the water would float it into the flume. ( A barrier across the drift would confine the water and coal and act as a feed mechanism).

Figure 6. Method of mining in Soviet hydraulic mines in gently dipping seams of average thickness.

I will discuss the expansion of the technology around the world in later posts.

On coracles, Partridge, the Mandan and the Inuit

A Passamaquoddy Legend:

In ancient days Partridge was the canoe-builder for the other birds. And after he had finished all the canoes, he called the birds together and each got into its bark and paddled off.

Oh, it was a great sight! First of all came the Eagle, in his big shell, paddling with the ends of his wings. Then came the Owl dipping his wings in the water, like the Eagle. Then the Crane, the Bluebird, the Robin, the Blackbird and the Snipe went sailing proudly after, uttering shrill cries or whistling and singing. And last of all came the tiny Hummingbird in a very tiny canoe; and for him good Partridge had made a prettily little paddle.

And the Fish-Hawk, who lives on the wing, skimmed over their heads, crying with amazement, as he saw the proud little fleet of canoes put out to sea.

“Why, O Partridge,” cried the Fish-Hawk, “have you no canoe for yourself?” But Partridge gave no answer, only looked mysterious and drummed; and the noise of his drumming sounded like an Indian at work on a canoe.

Then the birds sailed back to land, and all cried out, “Why, O Partridge, have you made no canoe for yourself?”

But Partridge shook his head, and said that when he built a canoe for himself, it should be a wonder such as no bird’s eye had ever beheld. This went on for some time until at last every bird knew that Partridge was making a wonderful boat for himself.

Now Partridge thought, “If a boat with two ends sails two ways, when then a boat, that is round, will sail every way.” So he built a canoe like a nest, perfectly round. And when it was finished, he called together all the birds to watch him put out to sea. And as they looked at the round canoe, they all cried out: “What a wonderful boat! We were not wise enough to think of such a thing!”

The Partridge, swelling with pride, stepped into the canoe, and dipped his paddle, But the boat made no headway at all, only spun around and around. And the harder he worked, dipping his paddle, first on one side and then on the other, the faster spun the canoe.

And when the birds saw what was happening, they fell to laughing, and mocking Partridge. And he left his round canoe, and, flying inland, hid himself for very shame under the low bushes.

And to this day he flies close to the ground, and hides under leaves and bushes. And the noise of his drumming sounds far and near like an Indian making a canoe.

Partidge had not been to Wales, nor to India, among other places where coracles are common.

Figure 1. Welsh coracle (Data Wales )

Figure 2. Indian coracle (Wikipedia )

It was in part the presence of the coracle that suggested to Meriwether Lewis as he and William Clark met the Mandan Indian tribe in what is now Washburn North Dakota that the tribe might have been descended from Prince Madoc ap Owain Gwynedd of Wales who lived around 800 years ago. (And would have travelled to America in roughly the same time frame as those reported to have left the Viking boats in Minnesota). It is, unfortunately, not something that can easily be checked with DNA testing, although, as an aside, it is now possible to get paternity testing in the Mandan region of the country. The last full-blooded Mandan, Mattie Grinnell, is reported to have died in 1971. Even by the time of the Lewis and Clark visit the tribe had been reduced from perhaps 15,000 individuals living in 9 villages, down to just two villages of around 1,200 people.

Figure 3. Mandan village – Bull Dance – George Carlin 1832 (American Art )

The village and tribe that Lewis and Clark met were largely wiped out in a smallpox outbreak in 1837. After the epidemic there were only around 100 survivors.

One of the difficulties in getting a true picture of the history of the Native American population prior to the large-scale migrations of Europeans across the continent, is that so many in those tribes died, due to the diseases that also arrived at that time. For example, by the time that the Pilgrims landed in Massachusetts it has been suggested that over 90% of the local native tribes had died, due to infection. (h/t Gregory ) Until recently the major cause of death was thought to be due to smallpox and viral hepatitis , a disease to which Native Americans are more susceptible but leptospirosis has also been now indicted, in the three to six year period that saw the majority of the deaths. Rats and mice from the many ships from different nations that were by that time visiting the continent would contaminate the environment in a way that made locals more susceptible, because of their lifestyle, than the booted and western-oriented visitors.

Regardless of cause, the diseases killed a dominant portion of the population, numbers suggested ranging from 75% to the 98% loss of the Mandan. The enforced migrations of the tribes, and the re-development of the land to fit European farming tradition has also lost a considerable part of the archeological record.

Further, when one goes back to around historic periods measured in tens of thousands of years ago, the maintenance of lineage lines and their origin becomes more difficult, and the need for larger sample sizes to draw realistic conclusions is offset by the reality that if the natives of the time lived on the coast-line, that region, around the world is now under considerable depth of water as the great glaciers have melted.

Yet the lack of evidence should not be considered equivalent to there being no evidence, and thence that these events did not take place. The evidence that the X variation in mtDNA migrated west seems conclusive, as Stanford and Bradley (S&B)have shown.

Figure 4. Distribution of the X mtDNA variation in the global population (Stanford and Bradley).

Having myself, in earlier times, studied how an early Stonehenge was made, after helping make one, the intelligence, and the long time over which events had time to occur back in those millennia, sometimes seems to get lost in current discussions over whether certain journeys and developments could have taken place.

S&B’s argument that local inhabitants of Siberia would, to have been able to survive, had to learn to create sealed clothing from animal/marine sources is a logical base on which to assume that boats, ubiquitous in other parts of the world, would have also existed in the far North. The example of the Thule Inuit, who travelled from Alaska to Greenland during the Medieval Warming Period, arriving in time to greet the Vikings and come down to us as the “skraelings” is well documented. The migration is generally thought to have been motivated by following the whale. It is a distance of on the order of 3,000 miles and while, at one time it was thought that this migration might have taken decades, or centuries there is now a school of thought that it might have occurred within a 2-3 year period, due to the use of dog-sleds and umiaks. The alternative reason that is now proposed for the short duration of the transition is also novel:

the Bering Strait Thule experienced a serious iron shortage related to disruptions in East Asian trade routes after the rise of Ghengis Khan in the 13th century. Knowing of sources of iron in the Canadian Arctic, Thule migrants set off on a journey eastwards in search of this precious commodity. The iron they eventually discovered would have been both meteoric (Cape York meteors) and European, because Norse Greenlanders were trading into the Eastern Canadian Arctic in their quest for walrus ivory and other Arctic luxury goods.

The image of a peaceful Inuit is also under challenge:

The emergence of hierarchical village societies, containing over-classes of artists and political leaders, and supported by slaves, is linked to their learning to hunt for the largest mammal in their environment, the bowhead whale. Intense competition for hunting grounds, over-population, and the ability to maintain permanent militias were factors in the emergence of violent conflict. Archaeologists have uncovered fortified Bering Strait villages, and the Thule were known to wear Chinese-style slat armour and use the Mongol recurved bow.

Conflict in the region was not just an event a thousand years ago it has been regionally common, even back to 13,000 BP. No wonder the Vikings had such a hard time in Western Greenland, and chose to leave L’Anse aux Meadows to its resident tribes. (But it might also explain where all those polar bear skins came from, that ended up going to the Vatican from the Greenland diocese.) (THE LOST WESTERN SETTLEMENT OF GREENLAND, 1342, An M.A. Thesis in History, by Carol S. Francis, California State University – Sacramento – Fall 2011).

Well this was more of a digression than I had intended when I started writing this post this morning, but rather it serves to illustrate, through the drastic loss of life when European and American cultures first met, and through the lack of much archaeological evidence until recently, the difficulties in generating a highly detailed history of events over the past 20,000 years.

I plan on writing about the Red Paint People next, and their arrival, and then we might get to the dissertation, cited above, and the discussion topics that it falls into regarding the interactions of Europeans and Native Americans in the MWP.

Camelina - a relatively new US biodiesel source

So what the heck is Camelina? Until I read that it was used as the greater source of the biofuel component for the test flight of the Japanese Airlines plane in February I must confess I had never heard of it. So since it has obviously got some legs (there was a greater percentage of it than of the algae derived fuel) herewith some thoughts picked up as I wandered through some Web pages, seeking more information.

Camelina in a Montana test plot

Apparently it came to the United States out of Europe, though it started out in Central Asia and the Mediterranean. In Europe much of the early cultivation of the crop has been replaced with canola fields, and it appears to compete with it as a crop. It arrived in Montana in about 2004 where it appealed both to farmers – as a source of omega-3 fatty acids, and to researchers who were looking for a source of biodiesel. The early work suggested that it could be sold more cheaply ($2 a gallon in 2005) than soy-generated biodiesel ($3 a gallon), but a cheaper price is hardly guaranteed to induce farmers to grow it. The oil has historically been used for cooking, with the meal fed to animals.

Recent interest in the plant was spurred by the omega-3 content

there is renewed interest in Camelina for its oil which is rich in the omega-3, alpha-linolenic acid (ALA).Ironically, this quality had contributed to its decline, due to difficulties with hydrogenating the highly unsaturated oil for margarine. Linseed (60% ALA) and Camelina (45% ALA) oils are by far the richest plant sources of omega-3.Rapeseed has lower levels of ALA (10%) and sunflower almost none. Camelina oil is more stable than linseed, due to its natural antioxidants, which also have health benefits in their own right.

It is a branch of the mustard family, and has the benefit over canola in that it is resistant to flea beetles, which are a problem for canola in Montana. Like canola it prefers cooler climates;for greatest yields being planted before the 15th – 20th March in Montana with harvesting in Late June to late July. (Similar dates hold for planting and harvesting in Wales.) Thus in 2006 there were somewhere between 7,000 and 20,000 acres planted in Montana, in 2007 this grew to 24,000 acres. It also has the benefit, over canola, of being able to survive drought and spring freezing. Further there is a winter variety that can be grown in areas with mild winters. The report from Montana State describes the oil content as:

Camelina oil has unique properties. The oil contains about 64 percent polyunsaturated, 30 percent monounsaturated, and 6 percent saturated fatty acids. Importantly, camelina oil is very high in alpha-linolenic acid (ALA), an omega-3 fatty acid which is essential in human and animal diets and has important implications for human health. The oil also contains high levels of gamma-tocopherol (vitamin E) which confers a reasonable shelf life without the need for special storage conditions.

In comparison to canola (rapeseed) which produces some 127 gal/acre camelina is reported to produce in the 62 to 100 gal/acre range.

Field trials of production showed a wide range of results from 330 to 1700 lbs of seed per acre, with oil content varying between 29 and 40%. There are however a significant number of varieties of the plant and thus tests have been carried out to determine which might yield the better crop given the Montana growing conditions. Optimal seeding rates seem to be in the 6-8 lb/ acre range, because the small size of the seed (400,000 seeds per lb.) apparently make it more difficult to ensure germination and achieve an optimal plant density of around 9 plants/sq. ft. It does apparently grow better when the ground nutrients are supplemented with nitrogen up to levels of 80 lb/acre.

The Montana report ends with the following

At this point there are many more questions than answers when it comes to camelina production and use. Early experience in Montana has shown that with good management, and timely planting, good crop yields can be attained. As a broadleaf cool season crop, camelina could become a good complementary crop to wheat, providing a needed break from cereals in wheat production. Crop rotation is a great way to reduce disease and insect pressure for any crop, and there are few good economic crop rotation options for wheat in Montana. Weed control is a major limitation to camelina production. Currently there are no herbicides registered for use with this crop, which means rescuing a field that becomes infested with weeds is difficult.

However varieties of the plant produces its own herbicide.

Data on crop production is still somewhat limited since the USDA did not start data collection until 2007, and the 2008 report was issued this April. Production in Montana in 2008 was significantly down (at 12,200 acres) over that of 2007. The average yield was 569 lb/acre, down 4.8% over 2007, though the range from 400 to 1000 lb/acre makes it unlikely that any conclusion can be drawn from those numbers.

The Welsh report comments on the current extraction process

Camelina typically contains approximately 35% oil. Cold pressing is not 100% efficient, the proportion of oil extracted being dependant on the type of seed and how well the press is set up.

As an example, a tonne (1000 kg) of Camelina will contain 350 kg of oil, of which the press will extract 250 kg. Cold pressing (400C) is required, because high temperatures will damage the antioxidants. Drought, lack of sunshine during seed formation, herbicide desiccation applied too early, and downy mildew infection may all lower the oil content of the seed.

In Wales they can get up to 1 t/acre.

Oregon is considering growing the crop after looking at trials in nearby states

Under dryland conditons in Montana, camelina is expected to yield 1,800 to 2,000 pounds of seed per acre in areas with 16 to 18 in hes of rainfall and 900 to 1,700 lb/acre with 13 to 15 inches of rainfall. Under irrigation, seed yields of 2,400 lb/acre have been reported. Three years of yield trials at Moscow, Idaho show a 2,100 to 2,400 lb/acre seed yield potential with 25 inches of rainfall.

. At present there are restrictions on the growing of canola in Oregon

Oregon officials in 2005 restricted canola-for-oil production in the valley to protect the valley's high-value vegetable seed crops. Officials recently announced they are going to renew the prohibitions.

"I would like to grow canola, but the state interferes with that, too," Van Leeuwen said.

Fears are canola will attract insect pests common to canola and brassica crops and that canola will cross pollinate with cauliflower and broccoli, lowering seed purity and eventually driving vegetable seed contractors out of the valley.

Camelina may overcome some of those concerns.

So my quick look suggests that it about on a par with canola (rapeseed) with some survival benefits over that plant as a crop, that it is only just being introduced into the United States as a crop and that, while it has potential, and there are some productive strains identified, it is still a little early in the game to know if it will pan out quite as well as the Biofuels Digest suggests.

P52. Pick Points

Half-a-dozen or so stories of interest:

With OPEC coming up on their next meeting this Sunday, I suppose it is time to guess whether or not they will make another production cut. The latest thought seems to be that they won’t. Though not all agree, and prices did dip a little Tuesday, back to $45.71. The EIA have forecast a decline in demand of almost 1.4 mbd, down around 200,000 bd over earlier forecasts. They see global demand dropping to 82.47 mbd, but they also see prices remaining lower, at slightly below today’s prices. They project natural gas at around $4.70 per kcf. We’ll just have to wait for the TWIP tomorrow to give us a little help to make up our minds. But these seem low.

To try and encourage demand Russia is dropping their export duty from $15.73 per barrel to $14.73 or more (depending on grade). Troubles in their oil patch are such, however, that the head of the oil-rich Bashkortostan region may be in trouble, and soon out of a job. The do have an agreement to run the Hungarian section of the South Stream pipeline, with a gas storage facility also being provided by the time it comes on line in 2015. (That date keeps slipping). Croatia is hoping to put a pipeline in place that would allow it to get its supplies through Hungary. Croatia uses 113 billion cu.ft. a year, but produces 60% of that in country. The rest comes from Russia.

There is talk of an LNG terminal in the Adriatic to help, and it is on the list that Exxon Mobil is anticipating for this year. The other is at South Hook in West Wales, and that is within weeks of completion. Meanwhile the new terminal in Rio de Janeiro will receive its first cargo today (March 11). It is coming from Trinidad and Tobago. The roughly 5 million cu ft tanker is on a test run to ensure that everything works well, before settling into production later in the year. While the terminal can produce up to 700 mcf of natural gas a day, the current thought is that may not be needed as much this year, as the water levels are relatively high, and Brazil uses a lot of hydro power. GDF Suez just brought one new plant at 241 MW on line last month. Brazil is one of more dependent countries on hydro-electricity with over 600 dams. and is pressing ahead with two more projects. Having seen power cuts in 2001, the government is determined that won’t happen again.

It isn’t quite that moist in the Middle East, where sandstorms have shut down ports in Kuwait and Saudi Arabia, they should end today. Not that this helps Japan, since Saudi Aramco continue to cut the volumes that will be shipped there in April. Because of sluggish demand, there was some thought that there might be another 15% cut in supply, but the Japanese think this unlikely.

There has been a bit of talk about coal reserves over at The Oil Drum, and Euan has just put up a post on Carbon Capture and Storage (that’s CO2). Some of the past debate has been about reserves and resources, and that was part of the reason for my Sunday post, since technology can change resource to reserve. Well so, apparently can state government. Some W. Va. Landowners got a shock in January when the coal under their property was reclassified from resource to reserve. This added some 3.7 million acres of reserve over last year, and with a tax bill of $100 an acre, both appeared to give the state a windfall, and unsuspecting homeowners sticker shock. The reassessments are being reviewed.

Well while the rest of the world waits to see how demand for more conventional fuel is going, up in Alaska the Iditarod is underway. And our trees are in bud, and crocuses came up in the year last week. Spring is a coming!!

More stories can be found at The Energy Bulletin and Drumbeat at The Oil Drum.