Excavation is normally associated with archaeology, while excavations done in the field of civil engineering are generally classified and included in a much broader term ‘earthworks’. Earth working is an engineering action that is done when massive quantities of soil or rock are moved. This act was done in a crude fashion several centuries ago. However, it slowly evolved as an exact science, with the engineers calculating the issues of soil fluidity, friction, quantity estimation, etc. so that the volumes of soil in the cuts or digs matched those of the fills.These calculations were done manually with a slide rule, using Simpson’s Rule and other similar methods. However, the advent of computers has brought in specialised software for these calculations.
Huge quantities of soil, rock and other materials had to be moved out in earthwork engineering due to the gigantic dams and other similar construction works that started in the last two centuries. This led to the birth of excavation and earth moving machinery and equipment like scrapers, loaders, trucks, graders, bulldozers, backhoes and dragline excavators. This equipment facilitated massive earthwork engineering in the construction of roads, dams, dikes, bunding, canals, tunnels, and in the mining industry. In fact, in Australia, the mining industry flourished in a big manner after the advent of excavators and other earth working machinery.
It will be interesting to know that the inspiration for the design of huge excavators was the simple steam shovel. However, modern-day excavators can dig and displace very large amounts of soil, mud and other material. Excavators have a cab type construction mounted on a rotating platform, sitting on top of an undercarriage that has got several sets of wheels or wheels with tracks. They also have an articulated arm type arrangement, which is known as a boom or a stick and there is usually a bucket type of attachment at the end of the boom. The cabs can rotate through 360 degrees for easier operation. The bigger excavators are referred to as caterpillar excavators, since their boom can bend like a caterpillar. Komatsu of Japan is known as the number one producer of hydraulic excavators in the world. Some of the excavators and earthmoving equipment suppliers in Australia can be found in the site kellysearch.com.
Excavations with these machines involve activities like digging of foundations, holes and trenches, handling of mud, soil, rock and other materials, demolition of existing structures, general grading and landscaping, heavy lifting like lifting and placing of huge pipes, river dredging, brush cutting with special hydraulic attachments, and last but not the least, mining, both open pit mining and underground mining.
The mainstay of the Australian economy is its mining industry. The mining companies of Australia that excavate precious metals and minerals contribute about 5.6% of the gross domestic product of Australia. In 2006-07, more than 80% of the mineral and petroleum resources were exported, which was about 49% of the total goods and service exports (Australian Government, Department of Foreign Affairs & Trade). Australia is the world’s largest exporter of coal, iron ore, diamonds, lead, zinc and zirconium, while being second in gold and uranium exports. This has been possible only by the advances in excavation technology achieved by that country and the expertise developed by the construction companies of Australia. The Sydney Harbour tunnel is a shining example of the advancements in the excavation technology in Australia.
