M INING O PALS & L IVING U NDERGROUND B ENEATH THE H ARSH A USTRALIAN D ESERT Over half of the residents of Coober Pedy is the largest opal Coober Pedy live underground mine in the world and it produces including hotels & recreation rooms 80% of Australia’s opals STEM Popular Lecture Series on Clarkston Campus of GPC 1:30 on Monday, September 17 th in Room xxx Dr. Dion Stewart, Professor Geology

* Coober Pedy Lies on the Edge of the Great Victoria Desert

After a paved road reached it in 1987, it became a tourist destination Black Opals

NASA – Rover Image

A Very Colorful Desert (movie sets abound) Mad Max Beyond Thunderdome Pitch Black Red Planet Sedimentary Rock Layers Top layer is a Red Sandstone Soil is deep red & almost pure sand Frequent Sand Storms are killers

[hide]Climate data for Coober Pedyhide MonthJanFebMarAprMayJunJulAugSepOctNovDec Record high °F Average high °F Average low °F Record low °F Precipitation Precipitation inches Source: Bureau of Meteorology [6]Bureau of Meteorology [6] Coober Pedy has a Desert Climate = Very hot days + Cool nights + Dryesert Climate

About 60% of the 1,900 residents live underground... Underground Storms have little effect Constant 75 o No heating... No cooling... Cost of construction about the same

“Down to Erth” -- Bed & Breakfast Tourists “love” underground living

Underground Church & Museum

Of course there is a Bar !!... for God’s Sake this is Australia

A postcard from Coober Peddy On the other side it reads.... “ Hi Mom, I slept here !! “

Coober Pedy – Is from Aborigine “kupa piti” meaning “White Man In A Hole” What does A tourist do? Mine tours “Coober Pedy Hat”

Tourism & Mining Don’t Mix Well Each mine starts with a vertical hole Claims are only 50 meters wide About 2.5 million holes in the ground

Prospecting shafts are made by using a Calweld-type drill which excavate holes from 9” to 6’ in diameter. The drills can dig to a maximum depth of about 100 feet. Opal layer down anywhere from 20’ to 80’ Opalized Clam Shell

Opal is in horizontal beds If cuttings show “opal”present in prospecting shaft then you have a mine !!! The “Drive” is the horizontal mining tunnel that follows the opal seam

Coober Pedy is the largest opal mining area in the world. If you wish to look for opal, you need to get a mining permit and an explosives permit, which requires a criminal record check by police, then you will be allocated a 50m 2 claim.

Eighty five percent of all claims in Coober Pedy have not produced opal. Claims are small and mines follow linear seams that may divide... No large mining company can make $ under such condition.... Thus everything is small

S MALL S CALE M ECHANIZATION.. Allows greater production

“B OGGERS ” Front end tunneling machines Opal still “hand picked”.. Waste comes out a chute at back of bogger.

Making a “Drive” Six foot shaft Lower tunneling machine down Put on the rotating blade Add telescoping pipe Pipe up Shaft to the Blower

#1 Waste “Mullock” goes up vaccum line #2 The “Blower Truck” creates the suction and line ends in the “Dust Bucket” #3 When full the dust bucket rotates, lid opens on bottom and a “Mullock Heap” forms.

Mullock Heaps stretch for miles across the mining area “very photogenic” Each one marks a once “productive” mine

Down 62 feet... Shaft at Blower... Driving toward “Colored Trace”

Recall there are 85x more prospect shafts than mullock heaps Accidents Abound “Tourists” no longer allowed to walk around in mining area unescorted

Noodling - The process of searching through heaps of discarded mullock for pieces of opal missed by the miners... Only with permission... Tourists pay. Some locals make a living by use of “ Noodling Machines” where mullock is passed through a darkroom on a conveyor belt beneath ultra violet lights, opal is fluorescent.

Opal Fluoresces “White” in Long Wave...UV Light

Opal – SiO 2. nH 2 O: Made by silica-rich, hot water solutions that often follow porous layers within ash beds or fine sedimentary rocks rich in quartz Solutions can replace pre-existing minerals ; Here a calcite, CaCO 3, shell has had all its molecules replaced by silica and water

Small sphere bring out “blues” larger sphere bring out “reds” Color cause by surface diffraction (not interior absorption of wavelengths)

The Australian opals are divided into three classes Coober Pedy’s are mostly Crystal & Some Black

Three Most Common Jewelry Production Styles Layered on top of “Potch”

Triplets The opal slice in middle can be as thin as a piece of paper

Slicing Machine has 220 blades cuts very thin slices lower left slices of opal below.. Rough ready to slice

Opal Mining Monthly Blog... All pictures step-by-step on hourly basis

If you go to Coober Pedy.... do some “noodling” with the locals... send me a postcard... &...stay out of the dust storms by living underground.