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The standard menthod for blasting rocks came to consist of drilling a hole to a considerable depth and depositing a charge of gunpowder at the further end of the hole and then filling up the remainder of the hole with clay or some other soft mineral substance, well rammed, to make it as tight as possible. A wire laid in the hole during this process was then removed and replaced with a train of gunpowder. This train was ignited by a [[slow match]], often consisting simply of brown paper smeared with grease, intended to burn long enough to allow the person who fires it time to reach a place of safety.
The uncertainty of this method led to many accidents and various measures were introduced to improve safety for those involved. One was replacing the iron wire, by which the passage for the gunpowder is formed, with one of copper. Another was the use of a [[safety fuse]]. This consisted of small train of gunpowder inserted in a water-proof cord, which burns at a steady and uniform rate. This in turn was later replaced by a long piece of wire that was used to deliver an electric charge to ignite the explosive. The first use of the latter method for underwater blasting occured in 1839 when [[Charles Pasley]] used it to destroy the wreck of [[HMS Royal George (1756)|HMS ''Royal George'']] at [[Spithead]] which had become a hazard to shipping.<ref>''The National Cyclopaedia of Useful Knowledge'', Vol III, (1847) London, Charles Knight, p.414.</ref>
While drilling and blasting saw limited use in pre-industrial times using [[gunpowder]] (such as with the [[Blue Ridge Tunnel]] in the United States, built in the 1850s), it was not until more powerful (and safer) [[explosive]]s, such as [[dynamite]] (patented 1867), as well as powered [[drill]]s were developed, that its potential was fully realised.
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