The Super Pit

The Kalgoorlie goldfields lie in a greenstone belt, consisting of volcanic and sedimentary rocks, all belonging to the Archaean period of the Earth's history, aged between 2.9 and 2.6 billion years.
Golden Mile mineralisation is characterised by a very complex pattern of closely spaced faulting.
There are over 800 ore lodes within the Golden Mile Dolerite over an area 5km in strike and 2 km in width, and to a depth of over 1 km.
Individual lodes may be up to 1'800 metres long, 1'200 metres in vertical extent and 10 metres wide.
Highest gold grades are typically associated with gold-silver mercury tellurides and alteration minerals with high vanadium contents.

Miner's huts encircled the mines
of the Golden Mile in the early years.

In June 1893 three Irishmen, Paddy Hannan, Tom Flanagan and Dan Shea, on their way to a 'strike' at Mt. Youle, stumbled upon gold immediately west of Mt Charlotte. Though they soon found in excess of 100 ounces they still had no inkling that the 'richest mile on earth'- the Golden Mile - lay some 3.1 miles (5 kilometres) to the south.
This was found soon afterward by Sam Pearce and Will Brookman, who pegged the ground that went on to become two of the most profitable mines of all times - the Great Boulder and the Ivanhoe.

The Great Boulder commenced operation with 30'000 pounds capital - and in the first year returned its shareholders three times that sum!
In the following year the return doubled, and the year after it added another 100'000 pounds, proving to be a veritable Eldorado for its backers.

Just down the road, the Lake View Console Mine averaged 10 ounces of gold to the ton in 1898 - current mines make do with not much more than 10% of that!
Little wonder this was 'The Golden Mile'.

A "frame-set" in the Golden Mine.

Nothing lasts forever, and between 1910 and 1920 many mines amalgamated, ore recovery rates reduced and jobs melted away. Many diggers left to fight the Great War and the population shrank.

In 1920 the pendulum swung back the other way, with gold prices soaring.
This recovery was short-lived and when the Depression hit the Mile was already struggling.

It was only when the Australian Government devalued the pound by 25% in 1931 that gold returned to profitability - and wealth returned to the Golden Mile.

As underground mining technology improved through the 1930s the need for labour decreased, and in 1939 large numbers of miners went off to enlist, exacerbating a plunge in production.

The Golden Mile from the air,

Recovery was slow after World War II, until the British Government devalued the pound in 1949, lifting the gold price by almost 50%.

Finally, in 1954 the Menzies government introduced a gold 'bounty' which was effectively a bonus for production in excess of the average annual production, and at last some stability returned to the Mile.

This was the origin of the Super Pit, Kalgoorlie-Boulder's famous landmark that will eventually stretch 3.8km long, 1.35 km wide and go down to a depth of more than 500 metres.

What had once been the Golden Mile, was named the Fimiston Open Pit, which in turn has become commonly known as the Super Pit.

Where small operations had once controlled the famous Golden Mile, Western Australia businessman Alan Bond started buying up the individual leases during the 1980s, seeking to create one big company and one big pit, from which gold could be extracted with massive equipment at a much reduced cost.

Smaller pits such as Great
Boulder, seen here in 1984,
were swallowed up by the
Super Pit.

Ore recovery rates had fallen so low, and underground mining had become so expensive that 'open cut' mining appeared the only way forward.

Significant changes - the most since gold was first discovered in Kalgoorlie by Paddy Hannan in 1893 - occurred.

It was now possible to mine far more economically - and to continue the harvest of the Golden Mile, which has produced nearly 50 million ounces of gold since the days of Paddy Hannan and his fortuitous Golden Quest.

Others who had embarked on quests of their own, including Bayley and Ford, Leslie Robert Menzies and young John Aspinall would doubtless be amazed at what their adventures have led to.

A substantial wall collapse in
the Horseshoe Pit on February 8,
1984, illustrates the lessons of
early big pit mining.

The start of true BIG pit trial mining,
on the top of what was known as
Associated Hill, 28/8/1987.

Work on the Horseshoe Pit
commenced in 1989 - it is now
330 metres deep!

The fleet of machines they use is pretty impressive in all aspects, not just its size ....

4 on site @$10 million each
Gross power 3714 hp
(2 engines)
Weighs 685 tonne
Fuel tank 11'000 litres
1 bucket full 60 tonne
Maximum speed 2.1 km/ph

1 on site @$2.4 million each
Gross power 880 hp
Weighs 99 tonne
Fuel tank 1'562 litres
45 m² Blade capacity
Maximum speed 20 km/ph
4 on site @$1.4 million each
Gross power 613 hp
Weighs 65 tonne
Fuel tank 1'109 litres
22 m² Blade capacity
Maximum speed 12 km/ph
31 on site @$4 million each Gross power 2'300 hp
Weighs 166 tonne
Fuel tank 3'790 litres
225 tonne payload
Maximum speed 55 km/ph
1 on site @$4.2 million each
Gross power 1'375 hp
Weighs 191 tonne
Fuel tank 4'641 litres
38 tonne payload
Maximum speed 23 km/ph
1 on site @$1.25 million each
Gross power 525 hp
Weighs 120 tonne
Fuel tank 795 litres
22 m² Blade capacity
Maximum speed 38 km/ph

LRDTH (Magpie)
A drill rig specifically built for use at KCGM by Ausdrill Ltd.
A hybrid of a Cat 350L loader and an LM8 front end.
This rig is used for drilling production holes in otherwise inaccessibly areas.
Reach of 12 meters.
6" hammer, 165 mm diameter hole size.

Used to drill pre-splits, probing, infills and batters.
Three on site with others brought in from Ausdrill Ltd as required.
A very versatile machine that has been used on this site in some form for over 18 years.
Single operator.

Modified by Ausdrill Ltd to meet KCGM specifications.
Used to drill production blast holes.
6 in operation on this site.
Also 2 DML's used (slightly bigger with more air capacity).
One of the DM45's has been converted to a fully remote machine.
This is used in areas we consider to be unsafe for personnel.
Believed to be the first (and only) one in the world.

Converted by Ausdrill Ltd to KCGM specifications.
Used for 'control in pit.
2 in operation on this site.
Holes up to 96 meters (plus).
1200 cfm / 500 psi (boosted).
Driller and offsider.

One of the visual impacts of the mining activity is the dust generated by open pits blasting.

To protect the community from blasting dust, the mine operates according to a Dust Monitoring and Management Programme, essentially involving avoiding surface blasting during unfavourable weather conditions based on forecasts from the Bureau of Meteorology and measured wind data.
Surface blasts may occur:
• If the wind is blowing blasting dust away from residential areas;
• If it is raining;
• If the explosives must be detonated due to safety reasons.

Waste rock doesn't contain gold or has gold in such low concentrations that it can't be economically processed.
Waste rock from open pit mining is trucked to and stacked in areas referred to as waste rock dumps.
Regular reviews and optimisation of dumping plans and trucking routes occurs to keep the dumps at short distances from the open pit.
The waste rock dumps are a significant feature of the landscape and are very visible.
The best design is one that will have characteristics of other landforms in the region.



No liability for timeliness, integrity and correctness of this document is accepted.
Last updated: Wednesday, 04.11.2009 10:08 AM