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Showing posts with label XRF. Show all posts
Showing posts with label XRF. Show all posts

Saturday, June 23, 2012

Tales of the Devil: Was it really a Gold Mine?


This is the end of the tunnel and with all the quartz veins exposed it sure makes you a believer, but subsequent tests failed to show any concentration of gold that exceeded the normal background level of gold.
Photo by Landowner


The question really arises is this thing actually a mine? The history of the area suggests that it may be something else; a tunnel excavated for the purpose of aging cheddar cheese. During the early 19th century the cheddar cheese production in the United States was in Goshen, Connecticut and spread out over several other towns in Western Connecticut. The most popular cheese that was produced was made in the shape of a pineapple that at the time was called pineapple cheese. This cheese whether it was made to look like a pineapple or simply cheddar cheese wheels. This cheese was so popular that it enjoyed a worldwide distribution being exported to the Caribbean, Europe and the Far East notably China.

The shaft and tunnel were recently rediscovered revealing a mine shaft that was about 40 feet deep with a tunnel going off from the bottom of the shaft that was 6 feet wide, 7 feet high and 10 feet deep. At the time of its discovery we all thought it was probably an abandoned mine but subsequent work that was performed on the mine with an x-ray fluorescence spectrometer (XRF) reveals no apparent minerals associated with gold or gold in this shaft and tunnel. So this left the question of what were they mining?

John Carter brought up the possibility that this was actually used for aging cheese. This hypothesis brought up one major objection from the landowner, and so far the other investigators are not aware of this possibility that what we thought was a mine was actually an underground tunnel used for aging cheddar cheese.

The major objection was the simple fact that this alleged mine was making quite a bit of water into the tunnel as well as part of the shaft. At first this seemed like a valid objection but further research reveals that they had hoses capable of carrying water clear back to 400 BC. Depending on the age of this feature it could have used hose made from leather that was secured by copper rivets, or a type of hose made from knitted linen fibers that were invented in the early 1800s. Either of these hoses was capable of being used as a siphon that would've kept the water in the tunnel under control.

In the early 1800s cheddar cheese was covered by a thin layer of cotton cloth then covered with lard causing the cheese to become waterproof. At the same time this covering of cotton cloth and lard allowed the gases that were being generated as the cheese aged to escape through the covering that kept the water from coming back into the cheese as it aged. However the cheese still had to be aged in a cool dry place which this was far from; it made water that was capable of filling the shaft about three quarters full. Without continually pumping the shaft and tunnel this complex was useless.

There was another kind of pump that have been used since ancient times called the Archimedes screw it used a helical screw turning inside a tight fitting to that was capable of raising water up to 10 m or close to 40 feet the depth of the shaft. It is possible they used a device like this for keeping the water out of the tunnel and shaft.

Had the complex been able to be used for aging cheese there would have been a series of shelves for storing the cheese, but once again these were missing so it has to be assumed that the whole complex was abandoned once the diggers were convinced it was useless for aging cheese.  The fact that further work was intended is attested to by a series of drill holes inside the tunnel.  Ultimately the vast amount of water entering the complex caused its abandonment.  This waterflow has been estimated to exceed twenty gallons per minute.  It would have been a pretty good well, but no place to store cheese.

Monday, August 8, 2011

Finding Gold through Soil Analysis

A diagram showing the different soil horizons.  USDA



The new method of finding gold deposits through soil analysis has proven to be extremely effective. The soil is taken from the B horizon that is the layer below the A horizon the layer of soil at the surface containing organic matter. It works by finding soil that has anonymously high levels of gold or other elements. The average level of gold that is found in soil is about 5 ppb. This can be used as a background level of gold content anything above that is rated as an anomaly.

In practice soil tests are taken on a grid pattern; a good size to work with is a plot of land 400 by 400 m with samples taken every hundred meters. This will give you 16 points where you can take soil samples. The samples are then subject to an analysis checking for anonymously high levels of gold. Each analysis is noted that it's location on the grid with contour lines drawn between points of analysis. This is a quick way of finding places in the grid requiring further analytical work.

The size of the grid is entirely arbitrary where you can make it as large or small as you like by varying its spacing. Soil samples can be taken by digging through the A horizon with a shovel, or earth auger either hand or power operated. It is important to get a lower layer of soil below that which contains organic matter because A horizon soil can contain organic chemicals that can sequester different metals giving you a false reading.

When you find an area within your grid that indicates higher levels of specific metals you can include that area as a smaller grid where samples are taken every 10 m, and you can even refine this grid further until you actually pinpoint the location of a mineral deposit.

Soil analysis is a variation on geochemical anomaly mapping using soil as the matrix it is based on the theory that mineral deposits create an aura of metal ions in the surrounding soil that can be detected by an analysis. Geochemical anomaly mapping uses other matrices than soil including stream water, sediments, plants or other matter. This method also uses grid sampling is a way of finding anonymously high levels of metals beyond the background count.

The soil analysis method is the most accurate when it is possible in the field to use an X-Ray Fluorescence Spectrometer (XRF) for performing the analysis accuratly.