Safety fuse
Encyclopedia
The safety fuse is a type of fuse invented and patent
ed by William Bickford in 1831. Originally it consisted of a "tube" of gunpowder surrounded by a water-proofed varnished jute "rope". It replaced earlier and less reliable methods of igniting gunpowder blasting charges which had caused many injuries and deaths in the mining
industry. The safety fuse burnt at a rate of typically about 30 seconds per foot (1 second per cm).
.
For three centuries gunpowder was primarily used for military warfare. It was not until 1574 that gunpowder was first introduced to the mining industry, and it took until 1617 before it was first used in a large-scale mining operation—at Thillot
in France.
, were used.
If a spark was created the results could be disastrous to the work force, and this was a common occurrence. Miners and mine owners were aware of the dangers of the use of gunpowder in mining, as is evident in their instructions for handling the material. A mill in England preparing the material wrote in its instructions, "Whosoever is at Labour within or without the powder magazines
should execute his commission in such a respectful and revered silence as is seemly in such a place where (unless the Almighty in his Grace keeps a protective hand over the Labour) the least lack of care may not alone cause the loss of life of all present, but may even in a moment transform this place as well as its surroundings into a heap of stone."
The other major problem concerned the intentional ignition of the gunpowder charges. To provide some protection from the blast and the fumes, a nominated miner ignited the far end of the fuse which was intended to burn at a known rate. The miners, therefore, knowing the length of the fuse, could estimate the delay between ignition of the fuse and the ignition of the main charges. However, early fuses, known as filled "quills", had a tendency to either burn irregularly, "flash off", or break—either by separation or by "pinching" in the shot hole due to the tamping process. They could also be damaged allowing moisture in, which could cause them to smoulder
instead of burn and introduce a long delay. If the main charge failed to ignite, this was known as a misfire or "hang fire
", and the miners would need to wait before returning to the work face to set new fuses. Increasingly, miners in Cornwall in the late 18th and early 19th centuries were becoming badly injured as a result of suspecting that there had been a misfire and returning to the work face just as a smouldering damp quill ignited the gunpowder charges.
, moved to the heart of the Cornish mining district
near Camborne
; where at Tuckingmill he developed the first practical and reliable means for igniting gunpowder when mining, the "Safety Fuze". After earlier attempts at developing a safer way had failed, Bickford had an insight while visiting his friend who was a ropemaker. While observing his friend winding cord together to generate a rope, Bickford believed he could adapt the same method towards developing a fuse. This was done with the help of his son-in-law George Smith and a working miner, Thomas Davey: who were also Methodists.
Bickford invented a machine which would thread and weave two layers of jute
yarn (a shiny vegetable fibre), spun in opposite directions, over a small "tube" of gunpowder, the whole of which would then be "varnish
ed" with tar to waterproof the product. The outcome was the development of a fuse which when lit "the fire only travels along it slowly, rate of burning ... being about 30 seconds per foot." Bickford had developed a fuse which would burn for a known length of time, depending on the length of the fuse.
Bickford obtained a British Patent
for his device (No. 6159 "Safety Fuze for Igniting Gunpowder used in Blasting Rocks, Etc") on 6 September 1831. It was originally called "The Patent Safety Rod" but its name was later changed to the "Safety Fuse". It was supplied as a "rope" of about 0.375 inch diameter; and was sold at the time for about same price as its predecessor, quills, at three pence
per fathom
(6 ft, 1.8 m). Bickford also set up a partnership
with Thomas Davey, who gained twenty five percent of the profits for the first fourteen years.
Given the unreliability of fuses and means of detonation prior to Bickford’s fuse, this new technology changed the safety and conditions of mining. Due to poor record keeping or lack thereof, it is relatively difficult to determine the exact number of mining accidents and related statistics prior to the invention of the safety fuse. However "this fuse soon replaced the less reliable fuses which were made of straws or quills filled with black powder, thus greatly reducing the hazard of accidental explosions in mining or construction." Word of the reliability of Bickford’s safety fuse spread, and was soon in large demand across world markets.
Bickford’s fuse not only dramatically improved the safety conditions of mines around the world, but also contributed to the development of dynamite
. Alfred Nobel created dynamite in 1867, by moulding nitroglycerine and a mud-like compound found near his laboratories called kieselguhr into individual cylinders. At the end of each cylinder Nobel inserted a blast cap which could be ignited in one of two ways. First, by inserting a safety fuse into the blast cap and igniting the fuse, it will set the blast cap off a produce enough energy to detonate the dynamite. Second, it is possible to detonate dynamite by inserting a blast cap into the end of the cylinder and then by attaching an electrical wire into the blast cap and producing a current which will travel from the source to the blast cap will also set off the dynamite.
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
ed by William Bickford in 1831. Originally it consisted of a "tube" of gunpowder surrounded by a water-proofed varnished jute "rope". It replaced earlier and less reliable methods of igniting gunpowder blasting charges which had caused many injuries and deaths in the mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
industry. The safety fuse burnt at a rate of typically about 30 seconds per foot (1 second per cm).
Brief history of gunpowder
Documentary evidence suggests that the earliest fuses were first used by the Chinese between the 10th and 12th centuries. After the Chinese had invented gunpowder, they began adapting its explosive properties for use in military technology. By 1044 they were using gunpowder in simple grenades, bombs, and flamethrowers. Gunpowder did not reach Europe until the early 13th century, carried over from China by European traders and merchants along the old Silk RoadSilk Road
The Silk Road or Silk Route refers to a historical network of interlinking trade routes across the Afro-Eurasian landmass that connected East, South, and Western Asia with the Mediterranean and European world, as well as parts of North and East Africa...
.
For three centuries gunpowder was primarily used for military warfare. It was not until 1574 that gunpowder was first introduced to the mining industry, and it took until 1617 before it was first used in a large-scale mining operation—at Thillot
Thillot
Thillot is a commune in the Meuse department in Lorraine in north-eastern France.-See also:*Communes of the Meuse department*Parc naturel régional de Lorraine...
in France.
Sensitivity of gunpowder
One of the problems miners faced when introducing gunpowder into their operations was that it was relative easy to ignite when exposed to sparks, intense heat, or flames. The method used by miners to blast away rock involved drilling several holes across a rock face which would be filled with charges of gunpowder. In order to confine the gases produced on ignition, the gunpowder was confined within each shot hole by inserting a pointed rod known as a "needle" in the gunpowder-charged hole and then packing in soft clay and tamping it down to form a plug. The "needle" was then removed and replaced by a fuse. To prevent sparking, a copper needle and a non-metallic ramming rod, typically made from hickoryHickory
Trees in the genus Carya are commonly known as hickory, derived from the Powhatan language of Virginia. The genus includes 17–19 species of deciduous trees with pinnately compound leaves and big nuts...
, were used.
If a spark was created the results could be disastrous to the work force, and this was a common occurrence. Miners and mine owners were aware of the dangers of the use of gunpowder in mining, as is evident in their instructions for handling the material. A mill in England preparing the material wrote in its instructions, "Whosoever is at Labour within or without the powder magazines
Gunpowder magazine
A gunpowder magazine is a magazine designed to store the explosive gunpowder in wooden barrels for safety. Gunpowder, until superseded, was a universal explosive used in the military and for civil engineering: both applications required storage magazines...
should execute his commission in such a respectful and revered silence as is seemly in such a place where (unless the Almighty in his Grace keeps a protective hand over the Labour) the least lack of care may not alone cause the loss of life of all present, but may even in a moment transform this place as well as its surroundings into a heap of stone."
The other major problem concerned the intentional ignition of the gunpowder charges. To provide some protection from the blast and the fumes, a nominated miner ignited the far end of the fuse which was intended to burn at a known rate. The miners, therefore, knowing the length of the fuse, could estimate the delay between ignition of the fuse and the ignition of the main charges. However, early fuses, known as filled "quills", had a tendency to either burn irregularly, "flash off", or break—either by separation or by "pinching" in the shot hole due to the tamping process. They could also be damaged allowing moisture in, which could cause them to smoulder
Smoulder
Smouldering is the slow, low-temperature, flameless form of combustion, sustained by the heat evolved when oxygen directly attacks the surface of a condensed-phase fuel...
instead of burn and introduce a long delay. If the main charge failed to ignite, this was known as a misfire or "hang fire
Hang fire
Hang fire refers to an unexpected delay between the triggering of a firearm and the ignition of the propellant. This failure was common in firearm actions that relied on open primer pans, due to the poor or inconsistent quality of the powder. Modern weapons are susceptible, particularly if the...
", and the miners would need to wait before returning to the work face to set new fuses. Increasingly, miners in Cornwall in the late 18th and early 19th centuries were becoming badly injured as a result of suspecting that there had been a misfire and returning to the work face just as a smouldering damp quill ignited the gunpowder charges.
William Bickford
In 1831 William Bickford, an English merchant and a Methodist, originally from Ashburton, DevonAshburton, Devon
Ashburton is a small town on the edge of Dartmoor in Devon, adjacent to the A38 Devon Expressway.It was formerly important as a stannary town , and remains the largest town within the National Park, with a population of around 3,500...
, moved to the heart of the Cornish mining district
Mining in Cornwall
Mining in Cornwall and Devon began in the early Bronze Age approximately 2,150 BC and ended with the South Crofty tin mine in Cornwall closing in 1998...
near Camborne
Camborne
Camborne is a town and civil parish in west Cornwall, England, United Kingdom. It is at the western edge of a conurbation comprising Camborne, Pool and Redruth....
; where at Tuckingmill he developed the first practical and reliable means for igniting gunpowder when mining, the "Safety Fuze". After earlier attempts at developing a safer way had failed, Bickford had an insight while visiting his friend who was a ropemaker. While observing his friend winding cord together to generate a rope, Bickford believed he could adapt the same method towards developing a fuse. This was done with the help of his son-in-law George Smith and a working miner, Thomas Davey: who were also Methodists.
Bickford invented a machine which would thread and weave two layers of jute
Jute
Jute is a long, soft, shiny vegetable fibre that can be spun into coarse, strong threads. It is produced from plants in the genus Corchorus, which has been classified in the family Tiliaceae, or more recently in Malvaceae....
yarn (a shiny vegetable fibre), spun in opposite directions, over a small "tube" of gunpowder, the whole of which would then be "varnish
Varnish
Varnish is a transparent, hard, protective finish or film primarily used in wood finishing but also for other materials. Varnish is traditionally a combination of a drying oil, a resin, and a thinner or solvent. Varnish finishes are usually glossy but may be designed to produce satin or semi-gloss...
ed" with tar to waterproof the product. The outcome was the development of a fuse which when lit "the fire only travels along it slowly, rate of burning ... being about 30 seconds per foot." Bickford had developed a fuse which would burn for a known length of time, depending on the length of the fuse.
Bickford obtained a British Patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
for his device (No. 6159 "Safety Fuze for Igniting Gunpowder used in Blasting Rocks, Etc") on 6 September 1831. It was originally called "The Patent Safety Rod" but its name was later changed to the "Safety Fuse". It was supplied as a "rope" of about 0.375 inch diameter; and was sold at the time for about same price as its predecessor, quills, at three pence
Penny (British pre-decimal coin)
The penny of the Kingdom of Great Britain and later of the United Kingdom, was in circulation from the early 18th century until February 1971, Decimal Day....
per fathom
Fathom
A fathom is a unit of length in the imperial and the U.S. customary systems, used especially for measuring the depth of water.There are 2 yards in an imperial or U.S. fathom...
(6 ft, 1.8 m). Bickford also set up a partnership
Partnership
A partnership is an arrangement where parties agree to cooperate to advance their mutual interests.Since humans are social beings, partnerships between individuals, businesses, interest-based organizations, schools, governments, and varied combinations thereof, have always been and remain commonplace...
with Thomas Davey, who gained twenty five percent of the profits for the first fourteen years.
Impact of the safety fuse
Bickford’s fuse not only dramatically improved the safety conditions of mines around the world, but also contributed to the development of dynamite
Dynamite
Dynamite is an explosive material based on nitroglycerin, initially using diatomaceous earth , or another absorbent substance such as powdered shells, clay, sawdust, or wood pulp. Dynamites using organic materials such as sawdust are less stable and such use has been generally discontinued...
. Alfred Nobel created dynamite in 1867, by moulding nitroglycerine and a mud-like compound found near his laboratories called kieselguhr into individual cylinders. At the end of each cylinder Nobel inserted a blast cap which could be ignited in one of two ways. First, by inserting a safety fuse into the blast cap and igniting the fuse, it will set the blast cap off a produce enough energy to detonate the dynamite. Second, it is possible to detonate dynamite by inserting a blast cap into the end of the cylinder and then by attaching an electrical wire into the blast cap and producing a current which will travel from the source to the blast cap will also set off the dynamite.