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5 The Quarryman

Interviews with quarry workers consistently highlighted the vast knowledge and intuitive relationship that a quarry worker has with the material he/she works with on a daily basis. From a business perspective, not understanding the geological composition of the stone can lead to huge financial loss, where stone is not harvested or the correct layer of stone is not targeted for extraction. Knowledge in the stone industry has been passed from father to son, similar to the work lineage of stone masons. In an interview with Herbert Frances[lb9] , a retired quarryman in Portland, England, the fascinating social history of a quarry workers lineage is discussed. Attraction to quarry work was largely determined by your geographical location; in 1920's Portland, quarries were the main source of employment for boys leaving school at the age of 14. Herbert also hints at the reciprocal energy stone and man enjoy reminiscing about the quarry songs with his work mates as they build a working rhythm to carve out the stone from the quarry.

Quarrying is difficult work, but to some extent the quarryman is assisted by nature. Most stone is found in the earth with conveniently placed horizontal and vertical cracks. The horizontal cracks follow the bedding plane in sedimentary rocks or the lava flow in igneous rocks. The pressure of the earth conveniently cracks the stone at a more or less right angle to these horizontal cracks, creating approximately rectangular blocks. These cracks facilitate the removal of stone; without these gifts of nature the removal of stone in ancient times would have been more difficult. It is as if the stone comes perforated for easier removal. The cracks also limit the size of dimensional blocks meaning that most stone has a natural size limit.

 

Quarryman Neil Swinbank describes the bedded layers of St Bees sandstone Corsehill quarry, Annan, ScotlandNaturally ocurring vertical and horizontal fault lines are exploited for the removal of block in the Three Castles Kilkenny blue limestone quarry, McKeon Stone, Co. Kilkenny, Ireland

 

Over the centuries, quarrier's have used any of a number of creative tricks to open up these pre-existing cracks. The initial effort would always be to pry the stone faces apart, first opening up a small gap. Each time the gap is opened a bit more progressively larger stones are dropped into the gap. When levering one of the stones out doesn't work, these cracks can be expanded in any number of creative ways.

When a natural crack does not allow the stone to be freed or it does not occur in the place where it is needed, the line of the split can be chosen by drilling new holes or carving a channel. Wedges are used to put increasing pressure into the holes until the stone eventually cracks along the dotted line implied by the holes. In the past wooden wedges were used, sometimes wetting them until the swelling of the wood splits the stone. In cold climates cracks or drilled holes were sometimes filled with water so that when the water froze it would crack the stone. Metal wedges are most commonly used today[lb10] . A combination of wedge and little cloaks (called pins and feathers) makes it less likely that the wedge will get jammed in the hole. The principle is one of expansion and it can equally be gentle or violent.

"The violets in the mountains have broken the rocks."

— Tennessee Williams

Explosives have also been used instead of expanding wedges, essentially doing the same thing. Explosions, however, worry sculptors and others who use dimensional stone because they have been known to introduce tiny cracks and ruin the stone for carving.

 

Quarrymen in the Sadahalli granite quarry split a long length of granite prior to right angled sub-division into manageable and marketable block dimensions.Detail of a line of overlapping cores, which is the methd used to extract blocks of marble in this quarry near Qu Yang, HeiBei, China

 

Softer stones can be extracted by channeling or sawing. Any means at the worker's disposal is acceptable. Quarrying can give rise to great practical creativity. There is even a quarry in China that cuts stone out with a core drill. The removed cores become another by product of the quarrying. Thermal cutters are increasingly used to extract hard stones like granite. Powerful jets of water can also cut stone.

Splitting stone is one of the earliest and most ancient quarrying techniques, and it continues to be widely used. Finding the grain (there is always a grain) means that you can split the stone with fewer swings of the hammer. To delve sometimes means to split the stone but delving also means to be able to divine the grain in a stone, a preparation that can direct your actions.

There are terms for the three axis along which the stone can be split: the easiest axis to split is called the 'rift;' the 'grain' is a bit harder, and for the third axis, the name tells everything, it is called the 'hard way.'

Anthropologists in China and elsewhere have shown that in ancient times pieces of very hard rock's like Jade were cracked off with the help of fire. Fire was used in medieval European cave quarries and it is still being used today in some open quarries in India[lb13] , often alongside modern techniques.

In these Indian quarries a small very hot fire is built over a square chisel that was previously sunk into the stone. The heat travels down the shaft of the chisel and starts a horizontal crack. The workers know the sign of when the crack has started. They can confirm this by tapping the stone with a hammer and listening for a hollow sound. After the crack has started, the workers slowly expand it by flaming out surface fires in expanding arcs. Spreading the crack is a slow process of about one metre an hour.

Until recently and still in some places the quarrying in softer rocks was done with stone axes. A channel cut the stone along a line where the stone was to be broken. This cut was made deeper and deeper until the stone could be dislodged. Sometimes instead of splitting or channeling the blocks of stone are sawn out.

In Neolithic times it was discovered that sand could cut through stone. Holes in prehistoric stone axe heads were cut using hollow reeds filled with sand. The reed was spun around slowly until the sand carved a small channel. This channel held the sand in place as the spinning reed bore deeper and deeper until a complete hole was made.

An early form of a saw translated this circular motion into a linear one by using a string or rope to push the sand back and forth. Eventually wire replaced the spun string. This technique was in common use until recently when diamond fragments began to be embedded in the wire. Metal saw blades were sometimes used to push the sand. In recent years chain saws have been developed to saw into stone.



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