Creative Exploration Geology, part 3.
By: George S. Green, B.A. Geol.
© 2008 George S. Green
All Rights Reserved.
When you institutionalize something that is conceptually flawed, you cast that flaw into the structural geometry of the institution itself. Since geometry influences by way of suggestion, this suggestive pressure will cause those persons sequestered into that institution, to come under the influence of this flaw. They will pick it up as if it were part of their profession and with out realizing it, they will replicate it as a valid manner of practice, as if it were a matter of fact.
If geologists were in their own institution, they could separate themselves from this flaw and its influence. They could weed it out and develop a manner of exploration practice more consistent with their own science. If they remain within a conceptually flawed institution, they will become subservient to it. They will replicate the flaw without seeing it. They may become so wedded to it that they will endeavor to defend it, as if it were part of their livelihood. As much as this, has already happened. That is why we now have this conceptually flawed institutional arrangement.
When a flawed perception enters a formula orientated approach to exploration practice, errors occur. Take the case of coal reserve calculations.
Some people think, that you proceed by first determining the density of the coal (expressed as grams per cubic centimeter or enlarged to kilograms per cubic meter) and then you determine the volume of coal within the coal deposit (expressed as total cubic meters), and then you multiple the density times the volume to arrive at a total number of kilograms of coal within the deposit (converted upwards to total metric tones). This should give you a total tonnage figure for your coal deposit.
This final figure is further reduced by the percentage amounts of ash (dirt) and water in the coal. So if there is 7% ash and 3% water (by weight) in the coal, this reserve estimate must be reduced by these amounts respectively. And this would seem to be a logical approach. However, in reality there are two problems.
The text books will tell you, that to determine the density of a mineral (ore) like gold in quartz, you divide your sample's weight in air by the difference between its weight in air minus its weight in water.This gives you a density figure (expressed as; grams per cubic centimeter) which you can use to calculate total "ore" reserves. This works fine for gold and other hard (dense) minerals. But it does not work for coal!
You can not use this 'text book' method to determine the density of coal because there is an unrecognized conceptual flaw in this approach. However, it is the method that many geologists and engineers have, in the past, used to calculate the density of coal; and go on from there, to calculate total coal reserves. Where did geologists get this notion? It looks to me like they got it from the mining engineers who shaped the exploration environment that geologists belong too. It exists (or existed) as a conceptual flaw embeded into the exploration practice of both the engineer and the geologist.
Coal is a porous material; gold in quartz is not. Porosity affects volume. A coal seam that might be measured in the field, or in a core box, or upon a geophysical log to be 6 meters thick, is not really 6 meters of solid coal. Coal is a porous material. It is full of holes. So, 6 meters in the field, might in reality only be, 4 meters of solid coal. If you take it to be 6 meters thick and you multiply that figure times the length and width of the seam, you will produce an inflated volume figure. In this case by 30%.
In the above example, the coal's porosity has inflated the volume figure. In the case of the weighing of coal in air and dividing that weight by the difference between its weight in air minus its weight in water, the result produces a density figure for pure, non-porous coal.
Those pore spaces can be occupied by water, gas and or other minerals. If it is water, then that fraction is canceled out when being weighed in water. The result is a density figure more or less representative of pure non-porous coal. Multiply this figure times an already inflated volume figure and coal reserve over estimations will being to occur.
While the previous (density calculation) example works fine for hard rock minerals like gold in quartz. It does not work for coal. Do it for coal this way, and base your mine plan upon those figures and you will be in big trouble within a week of start up. And the first thing you will encounter is a production shortfall.
A 50% production shortfall, means that you over estimated your coal reserves by 100%. Your reserve figures are double what they should be. The porosity of your coal, plus any error with determining density figures, has created an error as high as 50%. This can happen for thermal coal, which usually has a higher degree of porosity than does metallurgical coal. A 10% production shortfall in metallurgical coal could mean a reserve over-estimation by as much as 20%.
When engineers and geologists make this kind of mistake, they are hard pressed to believe it. The usual reaction is to see it as something like higher than expected ash in the coal. This happens when the engineers and geologists look at their current production figures and compare them to their anticipated figures and see a higher ash to coal ratio than was projected to occur. Their conclusion seems logical. There appears to be more ash in the coal than they originally figured. However, they do not understand the real genesis of the problem. They are the victims of a conceptual flaw that has been cast into the matrix of their institutionalized perception of things.
To calculate coal reserves correctly, you need to determine what one cubic meter of coal weighs. It is a simple question. The answer will give you, a "volume to weight ratio" that automatically takes the effect of porosity upon volume into account and you do not have to worry about how you calculate density figures. How do you do this?
As an exploration geologist in the field, you take a core sample of your coal and you measure it. It will be essentially, a cylinder. The formula for determining the volume of a cylinder is; (volume) equals (pi) times (the cylinder radius squared) times its (height).
V = π r² h
Once you determine the core's volume, you weigh it. Now you have a 'volume to weight ratio' that automatically takes into account the effect of porosity on your little bit of coal. It will be more or less representative of the seam of coal from which it came.
Of course you do a number of samples, over the entire thickness of your coal seam to generate a representative sample; using your geophysical logs to locate horizontal splits in the seam which correspond to certain geophysical parameters. Anyway, you do enough sampling and testing to get a good picture of the coal seam or seams within your deposit.
Your 'volume to weight ratio' will be expressed as kilograms per cubic meter. Now you have a figure that you can use to determine total tonnage, because now you know what one cubic meter of coal actually weighs.
You determine the total number of cubic meters of coal within your deposit and you multiple that figure times the weight of one cubic meter of coal. You divide the result by 1,000 to get total tons. This will give you the total metric tonnage of coal within your coal deposit.
Next, you take this figure and reduce it by the percentages of ash and moisture (by weight) in your sample or samples averaged; and you end up with reserve figures that you can depend upon. Then you reduce it by 10% to provide for some built in insurance. This will function as a built in production surplus which may serve you well, if any other kinds of production problems occur. There should not be any "production shortfall" which could adversely affect your financial arrangements.
Coal mines that make this error will encounter trouble within the first month of production. For example; a production shortfall in thermal coal of 50% might occur. With respect to metallurgical coal the production shortfall might be 10%. Responsible people might reply that it was due to 'higher than expected ash in the coal'.
However, that view would simply be wrong. A closer examination might subsequently determine that thermal coal reserves were over-estimated by 100%. Met coal reserves were over estimated by some 20%. But because it was a conceptual error embedded in the exploration process, no one is likely to find or look for it there. They would not believe it.
Every time a truck was loaded with what was thought to be 100 tons of coal and taken to the processing plant, only 50 tons of coal came out. You would have to wonder where the other 50 tons went!
If you expected to get 10 tons of 'ash' for every 100 tons of coal and you ended up with 10 tons of ash for only 50 tons of coal, you might conclude that there is "higher than expected ash in the coal". (The weight of the extra ash might appear to account for the extra weight going towards the original tonnage figure.) The truck when weighed might actually weigh somewhere around its anticipated tonnage. This would also help to propel a conclusion that there appears to be 'higher than expected ash in the coal'.
Would anyone necessarily consider that reserves were never calculated correctly in the first place? Would anyone necessarily consider that there is a conceptual flaw in their conceptual approach to coal exploration practice? And that this conceptual flaw has imbedded itself into the matrix of the exploration practice and profession of engineer as well as the coal geologists?
Geologists, and indeed, many engineers should know better; but especially geologists. Geologists have been carrying out their exploration work as taught to them by engineers. It is the formula orientated approach to exploration of the mining engineer that geologists have been using. It is an approach to exploration that seems 'logical' yet fails 97% of the time, and geologists have yet to question it.
Where did this particular conceptual flaw come from? It appears to me to have come from an approach to exploration that has influenced geologists to use the same methods to calculate coal reserves, as they use to calculate ore reserves for hard rock minerals. Is it still in place? One would hope not.
Does there need to be an independent Association of Professional Geologists in British Columbia? In my opinion, absolutely! It seems to me that geologists need to get there act together in respect to their own profession. Geologists and engineers need to be separated into their own, suitably structured and mutually respected professional bodies. The public as well, should be able to see clearly that geologists handle exploration, while engineers handle production.
Geologists start things off with exploration and at some point in the effort, they hand things over to the mining engineers. Geologists and engineers already know this. But the historical intrusion of the mining engineer into the exploration side of this process needs to be definitively corrected, and geologists need to be the people to stand up and press for this correction.
Geologists need to be in their own organization, sovereign, separate and independent from an organization of engineers. This way geologists (principally) and not engineers can set the standards for exploration practice.
Geologists in British Columbia lack leadership. They lack a sense of integrity and pride in their profession. They need to be in their own professional association, so that from within that association, they can speak to issues that matter to them and the public in relation to the work that they do.
At present there is no association or organization in British Columbia that actually represents geologists. The Association of Professional Engineers and Geoscientists is a licensing agency. It is principally an association of professional engineers which was approach by the government of the day, at the behest of Bay Street, to assume responsibility for this task. It does not represent geologists. And to this province's shame, and that of the professional engineers involved, it was imposed upon geologists.
This is not the right way to do things. Whether it is coal exploration or minerals exploration, the inordinate influence of the mining engineer into exploration matters has to be corrected and geologists need to smarten up and form their own representative professional body.
And that is all I have to say on this matter.
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