The safety fuse is a type of fuse invented and patented by English inventor William Bickford in 1831. Originally it consisted of a "tube" of gunpowder surrounded by a waterproofed 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 burns at a rate of typically about 30 seconds per foot (1 second per cm).
Documented 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. [1] Gunpowder did not reach Europe until the early 13th century, carried over from China by Middle Eastern traders and merchants along the old Silk Road.
For three centuries gunpowder was primarily used for military warfare. It was not until 1574 that gunpowder was first introduced to the mining industry, [2] and it took until 1617 before it was first used in a large-scale mining operation—at Thillot in France. [3]
One of the problems miners faced when introducing gunpowder into their operations was that it was relatively 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. [4] The "needle" was then removed and replaced by a fuse made of straws or quills filled with black powder. [4] To prevent sparking, a copper needle and a non-metallic ramming rod, typically made from hickory, were used. [4]
If a spark was created, the results could be disastrous to the work force, and this was a common occurrence. [5] 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. [5] 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." [5]
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. [6] 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. [6]
In 1831 English merchant William Bickford 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 named Thomas Davey. [6]
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 "varnished" 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." [7] 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". [6] It was supplied as a "rope" of about 0.375 to 0.5 inches (9.5 to 12.7 mm) 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). [6] Bickford also set up a partnership with Thomas Davey, who gained twenty five percent of the profits for the first fourteen years. [6]
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." [8] Word of the reliability of Bickford's safety fuse spread, and was soon in large demand across world markets. [9]
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. [10] At the end of each cylinder, Nobel inserted a blasting cap which could be ignited in one of two ways. First, by inserting a safety fuse into the blasting cap and igniting the fuse. Second, by attaching an electrical wire onto the blasting cap and producing a current which would travel from the source to the blasting cap. [11]
Dynamite is an explosive made of nitroglycerin, sorbents, and stabilizers. It was invented by the Swedish chemist and engineer Alfred Nobel in Geesthacht, Northern Germany, and was patented in 1867. It rapidly gained wide-scale use as a more robust alternative to the traditional black powder explosives. It allows the use of nitroglycerine's favorable explosive properties while greatly reducing its risk of accidental detonation.
Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, carbon and potassium nitrate (saltpeter). The sulfur and carbon act as fuels while the saltpeter is an oxidizer. Gunpowder has been widely used as a propellant in firearms, artillery, rocketry, and pyrotechnics, including use as a blasting agent for explosives in quarrying, mining, building pipelines and road building.
A detonator, sometimes called a blasting cap in the US, is a small sensitive device used to provoke a larger, more powerful but relatively insensitive secondary explosive of an explosive device used in commercial mining, excavation, demolition, etc.
The percussion cap or percussion primer, introduced in the early 1820s, is a type of single-use percussion ignition device for muzzle loader firearm locks enabling them to fire reliably in any weather condition. This crucial invention gave rise to the cap lock mechanism or percussion lock system using percussion caps struck by the hammer to set off the gunpowder charge in percussion guns including percussion rifles and cap and ball firearms. Any firearm using a caplock mechanism is a percussion gun. Any long gun with a cap-lock mechanism and rifled barrel is a percussion rifle. Cap and ball describes cap-lock firearms discharging a single bore-diameter spherical bullet with each shot.
Pyrotechnics is the science and craft of creating such things as fireworks, safety matches, oxygen candles, explosive bolts and other fasteners, parts of automotive airbags, as well as gas-pressure blasting in mining, quarrying, and demolition. This trade relies upon self-contained and self-sustained exothermic chemical reactions to make heat, light, gas, smoke and/or sound. The name comes from the Greek words pyr ("fire") and tekhnikos.
A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some jurisdictions to manage their safety risks and reduce their environmental impact.
A shell, in a military context, is a projectile whose payload contains an explosive, incendiary, or other chemical filling. Originally it was called a bombshell, but "shell" has come to be unambiguous in a military context. Modern usage sometimes includes large solid kinetic projectiles, which are more properly termed shot. Solid shot may contain a pyrotechnic compound if a tracer or spotting charge is used.
A triggering sequence, also called an explosive train or a firing train, is a sequence of events that culminates in the detonation of explosives. For safety reasons, most widely used high explosives are difficult to detonate. A primary explosive of higher sensitivity is used to trigger a uniform and predictable detonation of the main body of the explosive. Although the primary explosive itself is generally a more sensitive and expensive compound, it is only used in small quantities and in relatively safely packaged forms. By design there are low explosives and high explosives made such that the low explosives are highly sensitive and high explosives are comparatively insensitive. This not only affords inherent safety to the usage of explosives during handling and transport, but also necessitates an explosive triggering sequence or explosive train. The explosive triggering sequence or the explosive train essentially consists of an 'initiator', an 'intermediary' and the 'high explosive'.
In an explosive, pyrotechnic device, or military munition, a fuse is the part of the device that initiates function. In common usage, the word fuse is used indiscriminately. However, when being specific, the term fuse describes a simple pyrotechnic initiating device, like the cord on a firecracker whereas the term fuze is used when referring to a more sophisticated ignition device incorporating mechanical and/or electronic components, such as a proximity fuze for an M107 artillery shell, magnetic or acoustic fuze on a sea mine, spring-loaded grenade fuze, pencil detonator, or anti-handling device.
A touch hole, also known as a cannon vent, is a small hole at the rear (breech) portion of the barrel of a muzzleloading gun or cannon. The hole provides external access of an ignition spark into the breech chamber of the barrel, either with a slow match (matchlock), a linstock or a flash pan ignited by some type of pyrite- (wheellock) or flint-based gunlock, which will initiate the combustion of the main gunpowder charge. Without touch hole, it would be nearly impossible to ignite the powder because the only otherwise access into the barrel is from the front via the muzzle, which is obturated by the projectile.
A visco fuse is a higher-quality fuse used for consumer fireworks. It is most commonly colored green, red, or pink and is found as a twisted, coated strand. It is also used to create delays in the firing of multiple firework displays for safety.
An Oxyliquit, also called liquid air explosive or liquid oxygen explosive, is an explosive material which is a mixture of liquid oxygen (LOX) with a suitable fuel, such as carbon, or an organic chemical, wood meal, or aluminium powder or sponge. It is a class of Sprengel explosives.
Drilling and blasting is the controlled use of explosives and other methods, such as gas pressure blasting pyrotechnics, to break rock for excavation. It is practiced most often in mining, quarrying and civil engineering such as dam, tunnel or road construction. The result of rock blasting is often known as a rock cut.
A drifter drill, sometimes called a rock drill, is a tool used in mining and civil engineering to drill into rock. Rock drills are used for making holes for placing dynamite or other explosives in rock blasting, and holes for plug and feather quarrying.
Dyno Nobel is a manufacturer of explosives. It is a wholly owned subsidiary of Incitec Pivot Limited operating in Australia, Canada, the United States, Africa, Indonesia, Mexico, South America, Papua New Guinea and Turkey.
The following outline is provided as an overview of and topical guide to mining:
In military munitions, a fuze is the part of the device that initiates function. In some applications, such as torpedoes, a fuze may be identified by function as the exploder. The relative complexity of even the earliest fuze designs can be seen in cutaway diagrams.
A grenade is an explosive weapon typically thrown by hand, but can also refer to a shell shot from the muzzle of a rifle or a grenade launcher. A modern hand grenade generally consists of an explosive charge ("filler"), a detonator mechanism, an internal striker to trigger the detonator, an arming safety secured by a transport safety. The user removes the transport safety before throwing, and once the grenade leaves the hand the arming safety gets released, allowing the striker to trigger a primer that ignites a fuze, which burns down to the detonator and explodes the main charge.
Thermalite is a specific type of fuse used in pyrotechnic applications. The product was designed to be used in cross matching safety fuses of the Bickford type. As safety fuse is designed to neither give nor take fire through the heavy fuse jacket, ignition may be achieved by punching a hole perpendicular to and through a safety fuse powder core, threading a piece of Thermalite or similar igniter cord through the hole, then gently squeezing the safety fuse with pliers or similar to bring the powder core into contact with the igniter cord. The Thermalite could be ignited by a match, or more certainly by a purpose made igniter, similar to a wire sparkler.
The Mine A.P. Improvised Type I was a British Anti-personnel mine of World War II.