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Tips for Blasting

Firstly we need to know what blasting is. It is a technically controlled, effective and safe way to break rock for excavation. It is primarily used in Civil Engineering, Mining and Quarrying for roads and dam construction.

What explosives are used for blasting?

It is a common misconception that dynamite or gunpowder are used for most blasting activities but it is rather the engineered blasting agents that account for approximately 90% of explosive material used.
Ammonium Nitrate mixed with either sodium nitrate or calcium nitrate is the most common product and pound for pound the more effective explosive.

What is involved in Blasting?

• Holes are drilled into the rock and filled with explosives. The more solid the rock the more explosives will be needed.
• Proper ventilation is required to remove not only the dust but also the combustion gases from the explosion. This needs to be done before work can be resumed.
• The rock then collapses once detonation takes place.
• The debris is removed and if need be reinforcing is put in place before further work takes place.
• The entire blast lasts up to 1 second.

Steps to be considered before blasting takes place:

• Fragmentation desired – take into consideration size of digging equipment and crushing equipment needed on the project.
• Rock quality/character – state of the area being blasted, is the rock hard or soft and is the area dry or wet.
• Site limitations – is the area to be blasted near other structures or properties.
• Safety limitations – are there any electrical hazards
• Equipment limitations – are all equipment needed for the project available

Random facts about blasting

• Blasting is now considered routine work in the mining industry.
• Geological or Geotechnical knowledge is needed to ensure effectiveness and safety.
• Blasting involves design and patterns, not just “blowing” stuff up…
• The result of rock blasting is often called rock cut.
• Mining and Construction are the 2 most common uses for explosives.

Sources:
www.wikipedia.org/wiki
www.railsystem.net
www.miningandblasting.wordpress.com

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About Karen Garner-Savory

I started working at Leads 2 Business in May 2009, and have served as Head of Department of Telesales and Administration from 2010 until the present. I oversee both the Telesales department as well as the Administration of our Johannesburg Office.

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Unusual Finds During Demolition, Excavation and Renovation

1. An entire Mosque discovered in apartment during renovations: Palermo, Italy. When the owners of the apartment in Via Porta di Castro bought the apartment, they started with renovations. They intended to knock down a wall to open the area, but discovered that the plaster was wet and when they cleaned the wet area, they found Arabic writing. The writing covered all four walls and the inscriptions are in gold and silver. The couple have left the mosque as they found it, not wanting to destroy history.
2. £50k jackpot in rare tiles found by demolition man: Southbourne, Dorset. When Stephen Malton was contracted to tear down the home of Victorian artist, Arthur Bell, he never expected to find a fortune in Delft tiles. Due to the eagle eye of his foreman, the tiles were saved from destruction as he stopped the team while they were pulling down a wall behind the fireplace, where the tiles were hidden. Due to a clause in his contract, Stephen has the right to keep any treasure found during the demolition process. This find is estimated to bring him £50 000.
3. Letter To Santa Claus From 1943 Found In A Chimney: United Kingdom. A young boy’s letter to Santa was discovered during the demolition of the chimney of a 1930’s house. The letter asked simply for a Rupert Annual, slippers, a silk tie, a pencil box, chalk, soldiers and Indians. Lewis Shaw, the builder whose crew discovered the letter, decided to find the author of the letter and make his wishes come true. He connected with David Haylock (who wrote the letter when he was six), and David was very excited to receive his Christmas wish from 1943.
4. Bethel Church (1905) demolition leads to time capsule extraction: Chicago, Illinois. During the demolition of the Ingleside Community Church of the Nazarene, extra care was taken during the removal of a cornerstone column. A time capsule was extracted and opened – a Tetley tea tin, containing religious documentation in Danish (or possibly Norwegian) and two U.S. pennies from 1899 and 1901. It is believed the capsule was added to the cornerstone by L.A. Larson, the presiding elder and person who built the church.
5. A Mysterious Discovery halts Demolition of House: Middletown, Pennsylvania. A hidden room and tunnel were discovered after a crew knocked out a wall during the demolition of a home. The local historical society visited the site due to the age of the building. They advised that it might have been part of the Underground Railroad and used as a speakeasy during Prohibition.
6. Pictures taken of “Mannequin” by Demolition Crew, only to discover it is a dead body: Merriam, Kansas. The disturbing discovery of a dead body was made by a demolition crew when a load of trash was picked up to move. Initially they thought it was a mannequin and started taking photos, while laughing. Then, the stench got to them and they called 911. Demolition was halted while investigators determined whether it was a homicide.
7. Convent Rubble Yields Priceless Relic: Christchurch, New Zealand. A large antique safe concealed at the back of the altar of the under-deconstruction Nazareth House convent in Christchurch was found by Paul King, Graceworks Demolition and Recycling boss, while he was working in the chapel. The caretaker managed to find a key that fit the lock and when they opened the safe, they discovered a sacred ceremonial monstrance. Paul returned the monstrance to the nuns who had been living there at the time of the earthquake and they were overjoyed.
8. Stripping of Cottage Wall leads to Discovery of 400-year-old Mummified Cat: Devon, United Kingdom. A mummified cat was discovered when builders stripped a wall in the bathroom of a house in Ugborough. It is believed that years ago, cats were put behind walls to ward off evil spirits and witches. Richard Parson, the owner of the house, has indicated that the cat will be placed back in the wall after the renovations are complete.
9. Demolition of Abandoned home leads to Surprising Treasure: Saint Cloud, Florida. During the demolition of a dilapidated home that had been abandoned by the owner(s), silver coins started pouring out of the windows of the house. The coins were gathered up by the crew and they found that there were 202 dimes, a few nickels, over a thousand quarters and 861 half-dollars. These coins had been hidden in the walls of the house in jars and the oldest coin was dated to 1917. The coins were handed to the city of Saint Cloud.
10. Treasure Hidden in Cooler Box: Johannesburg, South Africa. While digging up a six meter trench for a drainage system near a building in 10th Avenue, Rodgers Nkuna discovered a mud-spattered blue and white cooler box. The police were notified and when they opened it, they discovered R20 and R50 notes, estimated to a value of R1.5 million. It is unknown how long the cooler box had been buried there.

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Sources:
HTTP://WWW.ANSAMED.INFO/ANSAMED/EN/NEWS/SECTIONS/CULTURE/2013/08/27/PALERMO-MOSQUE-DISCOVERED-DURING-HOME-RENOVATIONS_9205871.HTML
http://www.dailymail.co.uk/news/article-3246619/Demolition-man-unearths-50-000-rare-tiles-hidden-fireplace-called-knock-artist-s-house.html
https://www.yahoo.com/news/letter-to-santa-found-in-chimney-wall-fulfilled-72-184511409.html
https://www.today.com/news/78-year-old-man-reunited-santa-letter-he-wrote-boy-t61511
HTTPS://WWW.URBANREMAINSCHICAGO.COM/NEWS-AND-EVENTS/2018/02/02/UNUSUAL-TIME-CAPSULE-EXTRACTED-FROM-BETHEL-CHURCH-DURING-BUILDINGS-DEMOLITION/
https://www.theblaze.com/news/2014/05/27/a-construction-crew-demolishing-a-home-was-forced-to-stop-after-a-very-mysterious-discovery

http://www.stuff.co.nz/the-press/news/christchurch-earthquake-2011/8113672/Priceless-relic-found-in-convent-rubble
https://www.telegraph.co.uk/news/newstopics/howaboutthat/5200089/400-year-old-mummified-cat-found-in-walls-of-cottage.html
http://yournationnews.com/construction-workers-find-surprising-treasure-during-demolition-of-abandoned-home/
https://www.iol.co.za/news/south-africa/mud-covered-treasure-box-found-in-edenvale-436810

Photo Credits:
Mosque, Palermo, Italy – Photo by Franco Lannino
Bethel Church, Chicago – Photo by Eric J. Nordstrom

About Cecile Van Deventer

I joined the L2Q Team in 2006, as a L2Q Support Assistant and have been the HOD since 2010. I supervise L2Q Bills, Daily Tender Bills, Control Lists and Directory.

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