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"Young Ellie's Village" 'LEVEL’ EarthCache

This cache has been archived.

Ellie&Rudi Mentry: All a bit sad and overgrown. Time has taken it's toll on the arch too. Reluctantly it's time to say farewell! ☹️

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Hidden : 01/15/2011
Difficulty:
2 out of 5
Terrain:
3.5 out of 5

Size: Size:   other (other)

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Geocache Description:

THE SITE VERY OVERGROWN NOW AND ESPECIALLY HARD TO SEE IN SUMMER

Coal was the fuel of the industrial revolution; the black gold which powered the old ‘British Empire’. COAL is energy rich mineral remains of organic matter many millions of years old. Coal replaced wood as the staple resource of the Industrial Revolution. The advances in engineering seen in that time simply would not have been possible without coal.

This earthcache is the remains of a coal mine. It is ‘drift’ mine sometimes called a level or a ‘slant’ to access an underground mineral deposit. Drift is a more general mining term, meaning a near-horizontal passageway in a mine, following the bed of coal. A drift may or may not intersect the ground surface. This kind of mining is done when the rock or mineral is on the side of a hill. The entrance to the mine you see in the REFERENCE PICTURE is still there. It is overgrown, but can be viewed from a public footpath.


An interesting social history can be viewed at this link http://www.agor.org.uk/cwm/

DO NOT CROSS ANY FENCES

Other than on Sunday mornings, there is plenty of parking near the Rock Chapel, the coordinates are given and there is footpath to the viewpoint

TECHNICAL INFORMATION

The South Wales coalfield is the largest continuous coalfield in Great Britain. It has an area of approximately 1000 square miles covering much of the old counties of Glamorgan, Monmouth and Carmarthenshire with a small incursion into South Pembrokeshire. At its broadest north-south extent, the coalfield is eighteen miles in width and the area is criss-crossed with numerous deep valleys running North- South and East-West where coal has been primarily mined and communities established.

These narrow valleys are separated by upland moors and hills that, both in the past and present, make direct communication between them very difficult. The coalfield is bowl-shaped which dictated that mining began at the rim of the bowl, or edges of the coal field, where coal is nearest to the surface. In the centre of the coalfield, or the bottom of the bowl, the coal is much deeper and more difficult to mine. An additional problem is that in an area of mountains and valleys, the coal seams are fractured and uneven, making mining both expensive and labour intensive. South Wales coal is of three varieties.

Anthracite, the deepest in the ground, is of the highest carbon content and is used for central heating, thus making it the last to be exploited from around 1880 onwards. Bituminous is nearest to the surface and is particularly appropriate for the smelting of metals. Steam coal is found in the heart of the coal field and was invaluable for use in the boilers of railway engines and shipping. As demand for these various types of coal arose at different periods, the respective regions of the coalfield developed separately.

"Observations on the nature and appearance of coal seams, which were deformed during the late Carboniferous Variscan orogeny, have been made over several years within a number of opencast coal sites located across the South Wales coalfield. The deformation of coal seams was dominated by brittle failure and subsequent movement along fracture planes. Examination of hand specimens and smaller-scale samples using a scanning electron microscope reveals the presence of two distinct types of small-scale, tectonic fracture markings within deformed coals. Striated fracture surfaces with prominent ridges and grooves can bear a superficial resemblance to shatter cones in appearance but are unique to coal in their tectonic setting and appear to have formed by static shear failure, whereas strongly polished fracture surfaces result from movement across fracture planes. Deformed coal seams are also affected by distinctive, large-scale, tectonic fracture sets. The extent of fracturing within coal seams can be assessed using different techniques including measuring fracture frequency directly, performing various strength and hardness tests, making relatively simple subjective assessments on the appearance of the coal or monitoring the size distribution of the coal product.

Drift mines usually access close to the surface deposits by tunneling in to the side of a hill. These deposits are now often accessed by stripping off the top layers of rock and soil, or 'over-burden'. This is open cast mining. By applying some of these methods within working these newer, modern opencast sites, it can be shown that large amounts of abnormally fractured coal were formed along coal-based thrust flats or detachments but that the distribution of fractured coal along detached seams is rarely homogeneous. Enhanced fracturing often occurred in association with the localised thickening of seams along small-scale thrusts or within coal duplexes.

The temperatures required for the development of the anthracite field, in the NW of the coalfield, are unlikely to have developed by burial within a normal continental geotherm. It is argued that the style of thrust deformation, in which several thrust detachments parallel to coal seams moved simultaneously, producing a progressive easy-slip thrust (PEST) style, probably required fluid over-pressuring in the coal seams for its development There is an outstanding record of Late Carboniferous mainly terrestrial sequences, with extensive collections of historically collected plant fossils and coals available for study. This includes a continuity of succession from the base of the Westphalian through the Bolsovian into the Stephanian. However there has been only minimal modern study in terms of extracting climate and environmental signals from this resource, which shows analogies to present day climate change. Interest in the Coalfield from this respect has grown due to activity relating to a potential Geopark, and new fossil sites have been discovered and enhanced by excavation.

The South Wales Coalfield has the most complete Westphalian macrofloral record anywhere on the Variscan Foreland or adjacent basins, with 135 biodiversity-meaningful morphospecies having been recognized. All of the standard macrofloral biozones of the Westphalian Stage have been recognized, although a detailed comparison with the Central Pennines Coalfields has indicated some discrepancies in the relative positions of the biozonal boundaries."

REFERENCES

The Geology of the South Wales Coalfield .. (Volume 6,7,10) - Geological Survey of Great Britain

("Young Ellie's Village" #.... A prospective linear series of caches through Cwmafan. This is the village the yet to be "Ellie Mentry" grew up in. Rudi came to live here in 1975 and he is still not from the village !!!!

Ellie and her friends used play here until a cow was lost into the colliery workings. Local children believe that they could still hear the ghostly cow.)

QUESTIONS

To claim this earth cache.

Please EMAIL me the answers ~ From the guidelines: You do not need to wait for permission to log. Requiring someone to wait is not supported by the EarthCache guidelines. You should send your logging task answers , then log the EarthCache. When I review your logging task answers, if there is a problem, I will contact you to resolve it. If there is no problem, then your log simply stands."

Don’t include the answers in your log even in an encrypted form..

1. Research question - what sort of coal was mined here and why?

2. USE YOUR GPS to estimate the depth of NON COAL WASTE FROM UNDERGROUND, (the colliery spoil that you see in the bottom of the picture), was used to raise the ground to today’s height, as part of the reclaimation project.

This will give you a perspective of how much uneconomic shale was left after the coal was extracted

3. OPTIONAL: Take picture from a view point, approximating the old picture, with your GPS.







Additional Hints (Decrypt)

Tb gb nccebkvzngryl gur cbvag jurer gur byq cubgb znl unir orra gnxra.

Decryption Key

A|B|C|D|E|F|G|H|I|J|K|L|M
-------------------------
N|O|P|Q|R|S|T|U|V|W|X|Y|Z

(letter above equals below, and vice versa)