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Dan N

Help Analyzing Placer Ditches

9 posts in this topic

Are these ditches just supply for hydraulic mining monitors  or are they ground sluicing? There is old patented (&fenced) mine property south of the road, no large pits, just some wider areas in the gulches. The area history is of gravels worked in the gulches and the decomposed material on ridges between gulches was also supposed to be gold bearing. A few hard rock mines are north and up hill of this area. I plan to detect around here a bit  and wonder if the wider portions of the ditches, top center and the two parallel north of road, were ground sluice areas or if this was all to water the mine south of the road.  Was any gold in ditch parts or just water? Should I focus on the hillsides and gulches and ignore the ditches?  Of course I will check it all, just wondering about the original use.

Ditches1 (2).jpg

Ditches2.jpg

Ditches4.jpg

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There are quartz veins and stringers, some with free milling gold, most are not persistent enough to develop. Lower Triassic granite and quartz diorite.

I am really not sure if detectable nuggets were found, this is not old river channel, but the decomposed granite between the gulches reportedly yielded gold by sluicing.

I think that there may be small pockets of quartz vein gold still in ground and detectable.

The ditch that supplied water to the pictured ditches is no longer whole or functioning.

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Ditches were dug for a lot of reasons other than mining. Ranching, agriculture, even just homes with a few fruit trees and maybe a little garden might have a ditch to supply them. Without a lot more info, its just real hard to look at an areal photo and say, oh, dig there! Plus ditches and old, unused road ways look a lot the same on air photos and Google Earth.

Often the most easily seen things on photos like this are the workings themselves.

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On 4/13/2017 at 10:14 PM, Reno Chris said:

Ditches were dug for a lot of reasons other than mining. Ranching, agriculture, even just homes with a few fruit trees and maybe a little garden might have a ditch to supply them. Without a lot more info, its just real hard to look at an areal photo and say, oh, dig there! Plus ditches and old, unused road ways look a lot the same on air photos and Google Earth.

Often the most easily seen things on photos like this are the workings themselves.

Thanks Chris. I got out there last weekend. I drove the roads and walked some of the ditches, finding riveted pipe bridging the ditch over a gully. There is little doubt that these ditches were for mining: There was a patented mine area that these ditches lead to and they were fed by the Sparta ditch, built to placer the Sparta area. No agriculture or homes, just range land.. This is in the Blue Mountains of Oregon, Sparta mining district. Crystal Palace Gulch, Corral Gulch, Pittsburg Gulch.  (Oregon Dept. of Geology report b-14A). Upon rereading Lingren ("Gold Belt Of Blue Mountains") I found that most of the placers at Sparta and Eagle Creek produced mustard grain to wheat grain size gold, so it seems that my old Whites GM-II may be of limited value. (or I need to be a lot better at catching faint signals) Outcrops of the gold hosting albite granite and exposed bedrock are rare. I suppose my next trip I should dig down in the gulches looking for bed rock and color. I had been hoping(with ditches) to figure where sluicing occurred before and therefore where they may have lost gold out the end of their sluice boxes or  ground area. Other than the ditches I can find little evidence of work...no big pits or unusual looking ground features.

  Below is the wide section of ditch from first posting Most of the ditch is narrow: not sure if this is just an eroded section or indicative of more work. I found no interesting targets detecting or color panning.

 

100_6632.gif

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Good report Dan.  I'm in Boise and haven't explored much of the historical mining districts near Baker/Sumpter but it has a lot of cool history.  I did manage to get through the gold nugget display at the US Bank branch in Baker City last summer and it was very impressive and certainly worth the time if you are in the area.  

 

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The ends of the ditches were near the workings - I'd look for workings if this is a historic placer areas. Usually workings are pretty easy to see. The gold size you mention are detectable with a metal detector, just not at any great depth.

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Thanks Chris. I will listen carefully to my GM2 . Still refining my best areas to prospect. I have found another area of interest that shows much obvious historic work. Stacker piles between numerous channels/guts all down the gulch.  Forested gulch, work not visible on G-Earth. 

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