Waterjetting 2d - Adding cracks to Nature

In the last few weeks I have focused on demonstrating, with examples, that water effectively removes material by penetrating into natural cracks in the material and causing them to grow. But what happens when there are not enough cracks to remove material at an economic rate? The modern approach has been to raise the pressure of the water so that smaller cracks grow faster, thus providing the production rates needed, but that option wasn’t available in the past.

I mentioned last time that miners in the Caucasus Mountains of what is now Georgia used the power of mountain streams to erode gold deposits over 3,000 years ago. Perhaps learning from that, when the Romans came to Las Médulas in Spain, some 2,000 years ago, they though of water again as a way of mining the gold-bearing sandstone of the local hills. And though they had to modify the initial idea, the result became the most important gold mine in the Roman Empire. It is now a World Heritage Site.

Figure 1. Location of Las Médulas in Spain. (Google Earth)

The sandstone was more resistant than soil, and so the Romans came up with two ideas to improve the rate at which the gold ore could be removed. The first idea was to run galleries into the sides of the hills, creating large chambers underground, with support for the roof from wooden supports that were left in place.

Figure 2. Tunnel driven into the bottom of the hill at Las Médulas.

Figure 3. Underground room at Las Médulas.

At the same time that the mining preparations were going on local streams were being diverted and dammed so that a large volume of water was held in reservoirs and then carried by manmade channels to a point over the mining chambers. With the water ready, the timbers were set on fire, which initially weakened the overlying rock so that it began to fail, falling into the opening, and as the support burned away more rock fell into the opening until the cavity worked its way up to the surface. At this point the reservoir gate was opened and water flooded down the channel to fall into the cavity. As the water fell it further broke the rock into grain-sized pieces, and carried these down and out through the original opening in the hillside.

Figure 4. A Collapsed cavity, not the two figures at the arrows to get a sense of scale.

The water and debris flow was directed into flumes, in much the same way as modern miners in Alaska practice today, except that where carpet is used to catch the gold particles in Alaska, in Spain the Romans used plant stems (silex) to catch the gold. After drying the plant could be burned, easing to recovery of the gold. (In more modern times Spanish miners have lined the flumes with oxen hides.)

Figure 5. Artist sketch of the troughs used to capture the gold particles at the Spanish mines.

The use of heat to weaken rock before using water pressure for cutting has been tried with a couple of interesting wrinkles both by researchers at Rolla, and at the then U.S. Bureau of Mines and in Colorado, among others. But those more modern trials will be described later in the series. Using water streams to erode surface outcrops of mineral survived as “hushing” in the North of England and elsewhere until fairly recently.

Move forward some 1800 years or so from Roman Spain, and at the turn of the 19th Century miners in both Russia and New Zealand had a problem in mining coal. In both countries there were good quality coal seams, but they sloped at a steep angle that made it difficult to move men around without their slipping and falling. It was also difficult to support the roof, which was achieved at the time by sawing wooden props to length and wedging them between the roof and floor. Both nations had the idea of modifying the Roman idea of using water to remove the mined coal, but coal was thought to be somewhat stronger and more resistant than the Spanish sandstone.

In the New Zealand case the mountainous countryside makes it expensive to drive roads and as early as 1891 wooden flumes were being used to carry coal to the consumer. However it was then realized that the water could be used to also remove the mined coal, particularly that which was left in regions of the mine where it was not safe for men to go. The coal was therefore initially blasted, and then the flow from the nearby streams was directed at the debris pile. The volume of water, and the slope of the mine combined to remove all the mined coal, often overnight, so that a new area could be worked the following day. It was not until 1947 that pumps began to be used to drive the water at greater pressures. At this point, with the higher pressures that pumping brought, it was no longer necessary to pre-crack and break the coal with explosives.

While the New Zealand coal seams outcropped at the surface in very hilly ground, the situation was somewhat different in the Donets coal seams in the Soviet Union, where the seams were thinner, and production was barely economic. The seams in these mines were much deeper than in New Zealand, and so jet pressure could be provided from the drop in height from the mine surface to the location of the large nozzle or monitor that was used to aim the water flow at the coal. As with the New Zealand experience the Soviet miners (at the Tyrganskie-Uklony mine) initially blasted the coal with explosives to weaken it with a high density of cracks, before applying the water. However the miners found that not only did the water double production (to 600 tons/shift) the streams were powerful enough that it wasn’t necessary to pre-blast the coal. The nozzle diameters of the time were up to 2-inches in diameter, and could throw a jet up to 60 ft.

Figure 6. Early Soviet underground coal miner

It was from these small beginnings that hydraulic mining began, it was, in its time the most productive method of mining gold in California, and was used for many years around the world for mining coal, and other minerals. But that again is a subject for more detailed discussion at a later time.

The combination of explosives and water power remains in use in harder rocks, particularly in South Africa in the gold mines. Here again the seams of gold are very narrow and can slope or dip at a steep grade, the working area is thus kept very cramped and difficult to work. By blasting the ore with explosive, it can again be moved with water pressure, although there is an additional advantage to water here that I will further explain when I write about cleaning rust from plates.

Gold, as is shown by the way it can be collected in flumes, is very heavy, and part of the problem in the South African mines is that small pieces can get trapped in small pockets on the floor of the seam. The higher pressure water flows can flush out these pockets driving the gold particles down to a common collection point. In that particular the practices haven’t changed that much in three thousand years.

The family DNA - Y-chromosome initial results

Back in June I began what I expected to be a very short series of posts on archeological and biological reasons for deciding when Europeans first came to America. It was motivated by the more European look in early illustrations to the Eastern Native Americans, as opposed to the more Asian look of those further to the West.

As I began to research the topic, however, a number of distractions began to appear, and took time to look into. I have now read about a dozen books on related topics, as well as visiting many Web pages. The study has rekindled my interest in my own ancestors, and I have scraped my cheek, and will soon spit into a tube, as ways of seeing what my own DNA will reveal. In the process of doing all this it seems as though, when my generation and the baby boomers who follow, reach a certain age we get more interested in the past. Thus the apparent growing success of the two recognized sites that provide autosomal DNA testing as well as the mitochondrial and Y-chromosome evaluations that have been the more traditional sources. (I base that on Bryan Sykes’ opinion in his book “DNA USA:A Genetic Portrait of America".) Professor Sykes is former Professor of Human Genetics at the University of Oxford, and Chairman of Oxford Ancestors, a UK firm providing DNA services. The two American sites are Family Tree DNA and 23andme. There will be a separate post to explaining the strides that have been made in the last decade in DNA testing, and why, for example, without seeing more than her DNA sample, the Actress could be told by one of these companies that she had brown eyes and curly hair (which she does), among other interesting information.

I began our own DNA study after reading Spencer Wells’ book “Deep Ancestry: Inside the Genographic Project". Dr. Wells is an Explorer-in-residence at National Geographic, and has been the person most clearly identified with the Genographic Project run by National Geographic, which takes samples of the DNA of different groups and ties them into the spread of mankind from their origins in Africa. The story he told was sufficiently intriguing that I persuaded my sister, the Nurse, to scrape her cheek and to send her sample off with mine to that program.

The reason to do both comes from the two different lines that can be traced back most easily for an individual. These are, for males, based on the Y-chromosome and parts of its structure that do not change from generation to generation, except only through variations that occur at very infrequent intervals Thus, in the particular part of the Y-chromosome that is studied, I carry the same information string as my father, and his father, and so on back through time. (The next post will deal with the mitochondrial DNA line through my sister, that marks the maternal descent).

Figure 1. The passing of Y-chromosome information from generation to generation. (By convention squares are male and circles represent females, and each line down represents a generation).

Because daughters do not inherit the Y-chromosome (otherwise they would be sons) a lineage can “daughter out” if all the children across a line are female, since there is then no path for the male lineage to continue – through that line – but, as I will explain in the next post, there is a part of the male ancestor that still makes it through, albeit in a different form in the autosomal DNA. (And if you want to read ahead you might look at Charts, Graphs and Diagrams).

Thus, by sending away the scraping from my cheek to the Genomic Project I received, about six weeks later, notification that my results had been posted. (The information is passworded and only that which I have approved gets used in the program, with as much anonymity as I seek to have. But, as you may note by my writing about it, I have chosen, for reasons I will later explain, to be quite public).

The information that I received was, relative to all that I now know is available, somewhat cursory. Simplistically it showed the path that my own particular ancestors trod, following the time of the male common ancestor (referred to as Y-chromosomal Adam) who lived about 60,000 years ago.

Figure 2. Path of my ancestors from the time of Y-chromosomal Adam until about 20,000 years ago. (I come from the Cro-Magnon line).

Simplifying the report, relative to the above path, my basic haplogroup (the term for the classification group for my DNA, of which more later) is haplogroup R1b, M343 (Subclade R1b1a2, M269). It is the most common group in Southern England, where 70% of males fall into this category. But the part where we reached England is not covered in the initial National Geographic report. Rather they just spell out the bit that led to Cro-Magnon man.

From the earliest time in Africa the group in which I fall started with a modification M!68 to the initial DNA. At that time, roughly 50,000 years ago there were believed to be only around 10,000 people of the homo sapiens type. And the group was thought to originate in the Rift Valley from which the individual with this marker moved up and out of Africa. The marker is carried by every non-African man today.

A second distinctive marker (M89) developed some 45,000 years ago, as the human tribes began to follow the herds of game into the plains of Central Asia. It is this herd following practice, which led into the herding cultures of the Lapp and other northern tribes across the Arctic perimeter and which, I believe, hastened the speed at which some of these migrations occurred. Although, as Spencer Wells notes in the video “The Human Family Tree” even if the migrations moved at only a mile a year, they had plenty of time to reach the different points along the way, in either the route shown above, or to more distant places such as Australia.

While some did move on to Australia (having had to develop ways of crossing the sea to get there) a smaller group (including us) moved further north and across the mountains and this group with the M9 marker, which developed around 40,000 years ago, spread over much of Eurasia.

The mountains divided the tribes here, some moved further East, to Siberia and then on to America, others went down to India, and others north of the Hindu Kush where the advancing glaciers of the time (about 35,000 years ago). The M45 marker is found as mankind was learning to make tools of other materials than just stone. Smaller flakes made it easier to make more precise tools, and needles were made from bone to make warmer garments.

With the growing cold my ancestors, now also carrying an M207 marker moved west. Some turned south down towards India, but the remainder move towards what is now Europe bringing a new marker M173 to mark their distinction. These were the first of the homo sapiens line to establish in Europe, where Neanderthals had predominated. (And for those wondering what happened to them, there was at least some inter-relationships since the average person today carries between 1 and 4% of the Neanderthal DNA.)

As my National Geographic report states:

This wave of migration into Western Europe marked the appearance and spread of what archaeologists call the Aurignacian culture. The culture is distinguished by significant innovations in methods of manufacturing tools, more standardization of tools, and a broader set of tool types, such as end-scrapers for preparing animal skins and tools for woodworking.

In addition to stone, the first modern humans to reach Europe used bone, ivory, antler, and shells as part of their tool kit. Bracelets and pendants made of shells, teeth, ivory, and carved bone appear at many sites. Jewelry, often an indication of status, suggests a more complex social organization was beginning to develop.

The onset of the Last Glacial Maximum drive humans south, into Spain, where they gave birth to Cro-Magnon man, who carried the M343 marker (as do I) and it is there that the National Geographic report ends. At the time of Cro-Magnon man, as Brian Fagan notes in "The Long Summer" were still hunting reindeer as they migrated through the passes, as the herds migrated through the valleys of south-west France. Ice at the time covered most of the UK.

Figure 3. The extent of ice during the last Glacial Maximum.

One of the options that National Geographic provides is that you can then send your sample to Family Tree DNA for further analysis, and for comparison with a broad range of other individuals who have sent in their samples. I have done that, and in future posts will let you know how that went, as well as passing on some of the information that we got from the maternal side of the blanket, through my sister's DNA, and also for the Actress and how they knew she has brown eyes.

P47. Pick Points

Half-a-dozen or so stories of interest:

Up in Canada Suncor expects to produce around 300,000 bd of crude from its operations in Alberta. But all is not well in those operations. The rise and then fall in petroleum prices has had a significant impact on the oil sands industry.

Companies financing oil sands projects out of cash flow have been relatively unscathed, besides suffering substantially lower stock prices and having to delay projects due to lower revenue. Companies financing oil sands projects on credit are up for sale at bargain basement prices. The most likely buyers of those credit-short companies are supermajors and sovereign wealth funds.

The Canadian and Albertan governments have lost substantial tax revenue because of rapidly rising project costs eating into corporate profits. Relatively more upgrader projects being delayed or cancelled compared to mining and in-situ projects contributes to less value-added in Canada and a lower tax base for those governments.

The article goes on to discuss the significant costs of a cap and trade rule for the oil sands, and the potential serious consequences to the industry if it chooses to ignore that coming freight train. The report anticipates a cost of $80 a ton for carbon from operations on the scale of the oil sands.

In order to help the industry the Alberta Government is slashing royalty rates. The Alberta Government has also set aside $2 billion for work on carbon capture and storage for the oil sands and coal. There are however some doubts that the effort will result in any significant benefit. The current article in National Geographic has stimulated debate on the issue. But it has also brought a note that, if America does not want oil sand crude, (or makes it difficult to buy through CCS legislation) then China is ready to move in and take the oil instead. In Australia, meanwhile, a company has suspended its work on underground sequestration due to the plunging prices of permits (the problem that Europe also has).

While wandering around the various websites looking for comment on the demonstration at the Capitol Power Plant yesterday (which was a lot less dramatic that the organizers had intended I suspect, and a lot less well attended, I came on a couple of other folk that had been watching the video feed. One of them was OpenMarket who quoted a couple of interesting reports about some of the downside of moving from coal to other renewable fuels. The Reports were: M. Harvey Brenner, Ph.D., “Health Benefits of Low-Cost Energy: An Econometric Case Study,” AWMA Environmental Manager, November 2005, and Adam Z. Rose, Ph.D., and Dan Wei, “Economic Impacts of Coal Utilization and Displacement in the Continental U.S., 2015” (Penn State University, supported by a grant from CEED, July 2006). These looked at the conditions that would occur with different coal future production levels. The results were along the lines of

An econometric model was applied to a hypothetical regulatory case study, whereby U.S. coal was replaced by alternative higher-cost fuels such as natural gas for the purpose of electricity generation. The model was used to estimate the premature mortality associated with increased unemployment and reduced personal income. The adverse impacts on household income and unemployment due to the substitution of higher-cost energy sources were estimated to result in 195,000 additional premature deaths annually.

Somehow I doubt if we will hear much of those findings.

Pemex is sticking to its target of 756,000 bd from Cantarell this year, even though apparently their own figures are showing production is dropping at 7% pa. They are having some success with the Tsimin-1 exploratory well that came in with 4,400 bd of oil, while the Cali-1 well in the Burgos project is producing at 9 mcf/d.

Russia is signing energy deals with Spain that include renewable energy collaboration. This might bring the Spanish oil company Repsol into working on the Yamal fields. Given that investors have been lukewarm to the latest news of Gazprom profits this agreement, and the promise of some Shtokman gas for Spain supplied as LNG starting in 2014, may be helpful, since it may bring in Spanish investors.

And a quick note on the coal situation in Bangladesh. Apparently the Chinese company that has been working on the Barapukuria coal mine has told the authorities that if the mine does not start this week, they would pull out. The operation is tied up in compensation claims.

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