Wednesday, May 08, 2019

Ticking Off a Bucket List - Super Pit

My interest to visit the Super Pit in Kalgoorlie, WA traced back to 2011 when I was involved in a study of Mamut Copper Mine in Ranau, Sabah to address some of the problems arising from the closure of the mining operation in 1999.

Mamut Mine Pit which is almost circular in plan view was 1.0 Km wide by 500 m deep at its peak operation. In comparison, Kalgoorlie Super Pit, is oblong in plan view is 3.8 Km long and 1.5 Km wide. Its depth is approx. 600 m.

Ever since Paddy Hannan, Dan Shea and Tom Flanagan found gold nuggets in Kalgoorlie region in 1893, thousands and thousands of man-hours have been spent digging for gold. Now, after 125 years, there is still no sign of stopping of the digging. With mega and powerful tools and machines to aid the digging, transporting and crashing, the pit is only expected to become bigger and deeper.

The tour guide did tell all visitors that there will come a time when mining will have to stop when it is assessed to be uneconomical to mine the gold field either because of diminishing deposits or too excessive depth. Ideas have also floated as to what to do with this huge hole. One idea is to construct a Formula car racing course inside the pit. Sound crazy but possible!

Mamut Copper Mine Pit.
Superpit abstracted from Google Map.
Kalgoorlie Gold Mine Super Pit.

I have been fascinated by the mega machines used for the extraction and transportation of the ore and waste rock. In this guided tour, we were driven to see some of the idle face shovels. At the pit edge, we also saw a few operating dump trucks. 

The face shovel each weighs 710 tonnes, 4020hp, 13,500
litres fuel tank and 68.5 tonnes capacity per each full bucket.
Dump truck each weighs 166 tonnes empty, 2300hp,
 3,790 litres capacity fuel tank and a payload of 240 tonnes.
Each tyre weighs 5 tonnes.


The economic viability of harnessing every bits and pieces of gold from the rock fragments is dependent on extraction technique and technology. At this point of time, the mine operator has yet to find an economic method to extract gold from a particular shale-liked rock. These rock fragments are currently piled and stored pending a viable technique of extraction yet to be found.

At the end of the tour, visitors were warned against picking and pocketing any rock fragment found within the mine compound. My guess is that they believe the rocks which are scattered around the site may still contain very minute traces of gold of which the extraction technique has yet to be found!

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