Blasting mat
A blasting mat is a mat usually made of sliced-up rubber tires bound together with ropes, cables or chains. They are used during rock blasting to contain the blast, prevent flying rocks and suppress dust.
Use
Blasting mats are used when explosives are detonated in places such as quarries or construction sites. The mats are placed over the blasting area to contain the blast, suppress noise and dust as well as prevent high velocity rock fragments called fly rock (or flyrock) from damaging structures,{{cite book|last1=Pal Roy|first1=Pijush|title=Rock Blasting: Effects and Operations|date=2005|publisher=CRC Press|location=Boca Raton, Florida|isbn=0-415-37230-5|page=29|edition=Illustrated|url=https://books.google.com/books?id=w0GrIkUNeIgC&q=blasting+mat}} people or the environment in proximity to the blast site.{{cite book|last1=Ghose|first1=Ajoy K.|title=Mining, Challenges of the 21st Century|date=2000|publisher=APH Publishing|isbn=8176481580|page=383|url=https://books.google.com/books?id=C5XyR0jHe8QC&q=blasting+mat}} The amount of fly rock can be reduced by proper drilling in the bedrock for the explosives, but in practice it is hard to avoid.{{cite book|last1=Wyllie|first1=Duncan C.|last2=Mah|first2=Chris|title=Rock Slope Engineering|date=2004|publisher=CRC Press|isbn=0-415-28000-1|pages=270–271|edition=4|url=https://books.google.com/books?id=yF0IeLRKjDMC&q=Tire+blasting+mat}}
Mats can be used singly or in layers{{cite book|title=Bulletin – Association for Preservation Technology, Volym 30–31|date=1999|publisher=Association for Preservation Technology|page=70|url=https://books.google.com/books?id=W75UAAAAMAAJ&q=Tire+blasting+mat}} depending on the size of the blast charge, the type of mat and the amount of protection needed. They can be used horizontally on the ground or vertically hanging from cranes or attached to structures. In the vertical capacity the mats are sometimes referred to as blasting curtains.{{cite book|last1=Whiteside|first1=P. G. D.|title=The role of geology in urban development|date=1987|publisher=Geological Society of Hong Kong|location=Hong Kong|page=170|url=https://books.google.com/books?id=OlxPAQAAIAAJ&q=%22blasting+curtains%22}} When used in blasting tunnels the mats can be placed in patterns designed to let the mats stabilize each other and to direct the discharge from the explosion out of the tunnel.{{cite book|editor1-last=Redmond|editor1-first=Steve|editor2-last=Romero|editor2-first=Victor|title=2011 Rapid Excavation and Tunneling Conference Proceedings|date=2011|publisher=Society for Mining, Metallurgy, and Exploration, Inc.|isbn=978-0-87335-343-4|page=276|url=https://books.google.com/books?id=Lpbe_nnYPqwC&q=Tire+blasting+mat}}
To prevent mats from being displaced by the explosion, they can be covered with layers of soil or anchored to the ground. Anchoring the mats is also essential when the blasting is done on an incline where the mats may slide down from the rock face.{{cite book|last1=Gustafsson|first1=Rune|title=Swedish blasting technique|date=1973|publisher=SPI [(box 20)]|url=https://books.google.com/books?id=b1u-mQEACAAJ}}
Blasting mats are often used in combination with blasting blankets as an additional layer over the mats. The blankets are larger than the mats designed to retain the fragments that have managed to pass through the mat. Blasting blankets are used for both horizontal and vertical blasting.{{cite book|editor1-last=Hansen|editor1-first=T. C.|title=Recycling of Demolished Concrete and Masonry|date=2004|publisher=CRC Press|location=Boca Raton, Florida|isbn=0-203-62645-1|page=284|edition=Illustrated|url=https://books.google.com/books?id=z4KM4Xrr6Y0C&q=blasting+mat}} Blasting blankets consist of a fine-mesh strong net or industrial felt from paper mills.{{cite book|last1=Gustafsson|first1=Rune|title=Blasting technique|date=1981|publisher=Dynamit Nobel|location=Vienna|pages=122–127|url=https://books.google.com/books?id=8tHZAAAAIAAJ&q=inauthor%3A%22Rune+Gustafsson%22}} Both mats and blankets are designed to let air and gasses from the explosion pass through the cover and retain fragments.
Knowledge of the proper use of blasting mats is required in order to obtain a blaster's certificate issued by organizations such as the WorkSafeBC.{{cite web|title=Blasting Examiners Protocols|url=http://www2.worksafebc.com/pdfs/blasting/blastingexaminersprotocols.pdf|website=www2.worksafebc.com|publisher=WorkSafeBC|date=1 May 2011|page=17|accessdate=25 September 2015|url-status=dead|archiveurl=https://web.archive.org/web/20130227202412/http://www2.worksafebc.com/PDFs/Blasting/BlastingExaminersProtocols.pdf|archivedate=27 February 2013}}
Blasting mats made from used tires can serve a double purpose as road stabilizers, or road surface, in locations where roads leading to the blasting site are unstable or nonexistent,{{cite web|last1=Goldberg|first1=Jerry|title=Construction mat formed from discarded tire beads and method for its use|url=https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US4801217.pdf|website=www.docs.google.com|publisher=United States Patent|date=31 January 1989|accessdate=25 September 2015}} or in areas where the surface needs to be protected from heavy machinery.{{cite web|title=What is BLAST MAT (a blasting mat)|url=http://www.blastmat.com/about.html|website=www.blastmat.com|publisher=BlastMat.com|accessdate=25 September 2015}}
Materials
A number of materials are used for making blasting mats and new materials with different properties are constantly being introduced into this field. The most common materials are strips of old tires held together by steel cables, mats woven from manila rope or wire cables, logs or conveyor belts. Layers of wire netting can also be used. Several methods of assembling a blasting mat are patented.{{cite web|last1=Alexander Robertson|first1=Thomas|last2=King|first2=John Alfred|title=Blasting Mats|url=https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US3943853.pdf|website=www.docs.google.com|publisher=United States Patent|date=16 March 1976|accessdate=25 September 2015}}{{cite web|last1=Wikner|first1=Per Folke|title=Blasting Mat|url=https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US3371604.pdf|website=www.docs.google.com|publisher=United States Patent Office|date=5 March 1968|accessdate=25 September 2015}}
Blasting mats made from rope woven on wires were first used during the construction of the IRT Third Avenue Line in New York City in the early 1900s. They were used to protect the surrounding buildings and were favored since they prevented fly rock but vented gasses.{{cite web|title=Wire Rope Blasting Mat|url=http://www.idealblasting.com/wireropeblastingmat.aspx|website=www.idealblasting.com|publisher=IDEAL SUPPLY, INC|accessdate=25 September 2015}}
Mats made from recycled tires can be fashioned in a number of ways depending on how the tires are cut. Some examples are tread mats, sidewall mats and mats from non-flattened sections of tires.{{cite web|title=Products|url=http://www.blastingmats.com/products/|website=www.blastingmats.com|publisher=Four Star Blasting Mats|accessdate=25 September 2015}}{{cite web|last1=Hammel|first1=J. R.|title=2,926,605 Blasting mats|url=https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/US2926605.pdf|website=www.docs.google.com|date=1 March 1960|publisher=United States Patent Office|accessdate=25 September 2015}}
File:Tread mat.jpg|Tread mat
File:Sidewall mat.jpg|Sidewall mat
File:Quarter tire mat.jpg|Quarter tire mat
Manufacturing
The manufacturing of blasting mats is integrated with the mining industry and many companies specialize in making mats,{{cite book|last1=Saarinen|first1=Oiva W.|title=Between a Rock and a Hard Place|date=1999|publisher=Wilfrid Laurier University Press|location=Waterloo, Ontario|isbn=0-88920-320-2|page=215|url=https://books.google.com/books?id=DL0bjwbGZ84C&q=Tire+blasting+mat}} especially those made from recycled tires.{{cite book|title=Resource Recycling, Volym 22|date=2003|publisher=Resource Conservation Consultants|page=48|url=https://books.google.com/books?id=7s30AAAAMAAJ&q=Tire+blasting+mat}}
Military use
When charges are used to dig foxholes, an improvised blasting mat made from whole tires tied together with rope to reduce noise and fly rock, is recommended in the A Soldiers Handbook (United States). A tarp may also be used as a blasting blanket.{{cite book|last1=Ledgard|first1=Jared|title=A Soldiers Handbook, Volume 1: Explosives Operations|date=2007|publisher=Lulu.com|isbn=978-0-615-14794-9|page=557|url=https://books.google.com/books?id=U6f-Qlmm6zIC&q=Tire+blasting+mat}}
Accidents
Over the years, a number of incidents with fatal outcomes have been caused by fly rock. In most of these, blasting mats were not used or they were placed over the blasting face in an incorrect manner.{{cite web|last1=Hill|first1=William|title=Dangers posed to highway 7 by hidden quarry flyrock|url=http://www.crcrockwood.org/CRC%20Library/HQ%20Flyrock%20Dangers%20ref.%20Highway%207.pdf|website=www.crcrockwood.org|publisher=William Hill mining consultants ltd.|date=10 December 2013|pages=9–13|accessdate=26 September 2015|archive-url=https://web.archive.org/web/20150928005211/http://www.crcrockwood.org/CRC%20Library/HQ%20Flyrock%20Dangers%20ref.%20Highway%207.pdf|archive-date=28 September 2015|url-status=usurped}} Such an incident occurred in August 2015, in Cape Ray, Newfoundland and Labrador when a {{convert|7|kg|lb|abbr=on}} fly rock travelled about {{convert|250|m|ft|abbr=on}} from the blast site
and crashed through the kitchen ceiling of a nearby house.{{cite web|title=Incidents like Cape Ray blasting mishap deemed rare|url=http://www.cbc.ca/news/canada/newfoundland-labrador/incidents-like-cape-ray-blasting-mishap-deemed-rare-1.3205477|website=www.cbc.ca|publisher=CBC News|date=27 August 2015|accessdate=26 September 2015}}
Although designed to prevent accidents, as blasting mats weigh between {{convert|3000|and|6000|lb|kg|abbr=on}}, they have also caused injuries when falling on workers on construction sites.{{cite web|title=Cicillini v New York City Tr. Auth.|url=http://law.justia.com/cases/new-york/other-courts/2015/2015-ny-slip-op-50530-u.html|date=13 April 2015|website=www.law.justia.com|publisher=Justia|accessdate=26 September 2015}}
Blasting mats must be thoroughly inspected before each use to ensure there are no blown out segments or broken cables, by a blaster. Blasting mats will deteriorate with each use to the point where they become ineffective for their intended purpose. Only trained experienced and adequately supervised crews should be used in the placement of these devices over a loaded shot. A common complaint is accidental breakage of bus wires, leg wires or pinching off the non electric tubes that may result in the misfire of the shot.{{cn|date=January 2018}}