THE VULTURE MINE BILL FEYERABEND OUR GOALS TONIGHT Understand a - - PowerPoint PPT Presentation
THE VULTURE MINE BILL FEYERABEND OUR GOALS TONIGHT Understand a little about the geology Understand a little about the mines history Understand a little about changing technology Understand a little about the mines role in
BILL FEYERABEND
in Arizona history
Now lets put all of that into a geologic context. Here is a geologic map
Source:http://repository.azgs.az.gov/uri_gin/azgs/dlio/575
That should give you a headache. Mapping at the Vullture gave me a headache until I understood the key. STRUCTURE
This is critically important.
The Vulture mineralization was introduced after the rocks were formed.
Mineralizing fluids needed a pathway. Structures provided that pathway.
Broadly, there are two styles of structural deformation: Compression which was dominant in the Mesozoic and early Tertiary time about 150 to 40 million years ago. Extension and lateral forces have dominated for about the last 40 million years.
Equally broadly, there are two styles of deformation. One is under extreme pressures of miles at depth where minerals deform differently under compression.. The other is closer to the surface where the rocks are brittle and deform by brittle breaking.
Lets go back and look at this image: Notice how it looks like the edge of a deck of cards: Watch this demo of applying a force to a deck of cards.
At the Vulture mine, you see:
A ductile zone of mid-crustal deformation. A later brittle deformation at much shallower depths along the pre-existing plane
Because we need an open plumbing system for the mineralizing fluids, we are going to begin with the extensional structural plane dipping moderately to the north.
North
Represent As A Plane
Here we begin with that simple planar structural surface. However, it is ‘tight’ and dry.
Having a brittle structural plane is not enough by itself.
You have to open it so fluids can flow.
There are two ways. The Vulture has both. Cross faults Warp the plane
Now you apply a force down and towards the viewer
warping and breaking it.
Now you mineralize the spaces opened by warping and breaking.
After mineralization continued forces juggle and offset the mineralization along faults. Some are 10s of feet, some 100s.
There is another point which favors the Vulture. Gold was deposited after sulfide minerals
not with them like the right slide (more common)
You can free the gold on the left by coarse crushing. You can free the gold on the right by: very expensive fine crushing roasting / smelting nature’s weathering (base of oxidation) That is why commonly pioneer mines went to base of oxidation and stopped. Vulture mine went to base of oxidation and kept going.
Vertical zonation – common epithermal characteristic Little change in temp pressure when 10 miles deep Big changes when 2,000 feet deep Temp and pressure rapidly decrease Get changes in what is precipitated
All of that is now dipping moderately to the north. If we go on the tour, at the overview you will be standing
looking down at the brittle structures hosting the mineral.
Now lets switch gears from geology to history and put it in a geologic context.
Johannes Henricus Wickenburg Born 1819 in Essen, Germany Essen is a coal mining region He mined coal with his brother
Emigrated to New York in 1847 and moved to San Francisco in 1853.
1853 1862 1863
1853 in California (a little late) 1862 at short lived La Paz placer gold rush 1863 at Peeples Valley where Rich Hill placers just discovered
Mining and particularly gold placer mining was a common thread thru Henry’s life.
Henry first saw the big white quartz outcrop in 1863 before AZ even became a territory. There was no practical way to record a claim – ownership was by possession. The location that stuck was this notice in 1864 recorded in Prescott.
Charlie Genung put up an arrastra in June, 1864 on the Hassayampa River about 12 miles west. They recovered enough gold from the first load of rock that the race was on.
The ‘big white tooth’ of quartz outcrop had dimensions of maybe 1800 feet long, 40-60 feet high and 50 feet wide. The first mining was simply quarrying of that rock mass. Soon there were tens of arrastras on the Hassayampa and several daily wagonloads carried from the mine. Henry got out of mining and into charging money. He charged $15/ton plus 1/3 of profits. Lawsuits were inevitable. At the first lawsuit in 1864, he documented income of $700/day for five months.
It took about a year to quarry down the discovery outcrop. Everything about it was ideal frontier –
and arrastra milling. Ore easily separated visually to +1 ounce Once mining started underground, the basics changed. Underground is complicated and demands capital. You had to invest money to make money.
PRODUCTION MINING – CLAIM OWNERSHIP
The habits of early prospectors were to claim “feet along the lode,” so you end up with claim maps like this. The largest 600’ and the smallest were 13’ 7”.
That worked OK when quarrying a quartz hill. It does not work so well underground. Haulageways, access to pods of mineral, milling, etc are complications. Production, development, milling, exploration and financing needs put pressure for consolidation.
PRODUCTION MINING – CLAIM OWNERSHIP
PRODUCTION MINING – CLAIM OWNERSHIP
Beginning with the Vulture Mines Co. 1866 purchase of part of Henry’s interest, there Is a pattern of capitallized groups acquiring the Vulture, running it for a few years They always ended up done in by faults – except when done in by management. Example – the Vulture Mining Co. used geology to find the extension across the Talmadge fault in 1911 and then lost it across the Astor fault in 1916.
PRODUCTION MINING – CLAIM OWNERSHIP Not all management was an improvement. James Sexton about 1868 was named manager. He financed the mine by credit – other peoples. When mine shut down in 1872 , unpaid bills: $12,000 to store owner George Bryan $82,000 to freighter JM Bryan Time described as “contentious circumstances” Sexton returned to Connecticut and reportedly built a mansion.
PRODUCTION MINING – CLAIM OWNERSHIP “The Vulture was my biggest mistake.” Horace Tabor – Colorado silver king – leased Vulture in 1887. Defeated by faults. Lose everything in the Silver Panic of 1893 and lost Vulture to unpaid taxes.
PRODUCTION MINING – MILLING The original arrastras crushed 1-2 tons per day. Stamp mills have existed since medieval times. First stamp mill on river built in 1866. An 1869 40 stamp mill on the river crushed 80 tons per day. Stamp milling was used at Vulture into 1930s.
PRODUCTION MINING – MILLING Stamp mills required: water fuel (wood) 1880 mill paid $100-150/day
You see variations of locating at one and bringing the other two 1879 a river – mine pipeline built 1880 End of milling on Hassayampa
PRODUCTION MINING – MILLING 1890s Cyanide first used 1930s Crushing by jaw and cone crusher, ball mill cyanide recovery using carbon
MINE TIMELINE
1860 1865 1870 1875 1880 1885 1890 1895 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 Discovery, arrastras First stamp mill, Civil War ends, Malaria, Gold $50 to $28 Contentious management, Fault, Water at 310, Indian attacks, Silver Panic 1873-75, Long depression, Unemployment 14% Water pipeline, mills on river stop, grades decreasing Small leasees Horace Tabor, mine sold for taxes Faulted extension found Re-working tailings, Robbing pillars Open pit, New Technology, New shaft, Sulfides
Lets recap history with a simple timeline.
MINE TIMELINE compared to cartoon geology
We can understand the ebb and flow of history from geology
THE VULTURE MINE – LASTING AFFECTS
Early description of Wickenburg: The Vulture mine and mill were going full blast. The company paid off every other Tuesday. Money was plentiful, wages high and all seemed to be good spenders. The town had five saloons and one restaurant. Town of Wickenburg
THE VULTURE MINE – LASTING AFFECTS
Henry Wickenburg used monies from sale of 300’
in Jack Swilling’s scheme to restore the old Hohokam canals along the Salt River. We now call that the Salt River Project and the town is Phoenix.
THE VULTURE MINE – LASTING AFFECTS
Grand Avenue cuts diagonally across the Phoenix grid because it was there first – to connect Phoenix farmers to their cash market at Wickenburg and the Vulture mine.
THE VULTURE MINE – LASTING AFFECTS
The historic connection
Hassayampa River was
to California. Gas was $0.115 / gal in 1908 at the Vulture station. Because of the water pipe, Okies during the 30s camped there to rest and pan placer gold in the washes to get enough funds to continue to California.
THE VULTURE MINE – LASTING AFFECTS
The Vulture camp is about as good as it gets to look at artifacts from the West and ponder the lives