Friday, February 01, 2013

Denver Mining Club talk on Fine Gold Recovery

                                           Now, THAT'S a Big Sluice Box, Boys!

Did you know that Denver has a mining club that was founded in 1891? I knew the Denver Mining Club (AKA Colorado Chapter of the International Order of Ragged Assed Miners) had been around a while, but I had no idea they had been here so long.  Their website, , is a wealth of information about its’ meetings, (they meet every Monday) founding fathers and their activities. Everyone was very friendly and did their best to make all of us feel at home.

At the beginning of their meeting, they had all new comers stand, introduce themselves, and tell their interest in or connection to mining.  There are no right or wrong answers, so all newcomers are voted into the Denver Mining Club or CCIORAM, and presented with a certificate that they are sworn to place in a prominent place in their home or place of business.

Larry and I were there attending a discussion about find gold recovery given by Phil Martinez, .  Phil had asked us to go with him, his wife Elsie and their oldest son Phillip Jr., to help with the computer stuff that his paper and crayons won’t handle.

Phil talked a great deal about the large placer operation he worked for that is located at the base of Mt. Elbert.  I won’t plug them here, so you will have to look up their name if you want to know about them.  According to Martinez, they were running up to 1,000 yards a day and their biggest problem was the sticky clay that ran with all of this material.

Their solution to the problem was to use a series of jigs to break up the clay, and to then, run all of that material into a bowl system.  As in all fine gold recovery, the name of the game is breaking down your material into a useable state where all material is of similar size, and then to run water and sluice boxes at a water speed and sluice box angle that is best suited to your circumstances.

Clay is particularly bothersome to everyone, and recovering the gold trapped in it is never easy.  Emulsification of the material is of great importance, but only if the values that can be found in the clay would make breaking it up worth the time and effort needed to do so. Testing is the only way to decide if your time is better spent running material that you can separate the gold from more easily, or to go after what is in the clay.

To maximize recovery in this large placer, the sluices needed to be adjusted from what Martinez called ‘ski slopes’ to a proper angle to keep from running the gold into the tailings ponds.  After this adjustment was made, the sluices were able to handle the volume of water running down them and capture the finer gold much better.  Recovery of the fine gold went way up.

As with all operations, testing should be constant, whether you are a large operation or a weekend placer warrior.  Then, watch your water speed and the angle of your sluice box for maximum fine gold recovery.  Flatter box, more water; steeper box, less water.  Those are the basics.  Depth of water and size of material also play important parts.  Keep tweeking until your sluice box is recovering 90% of what is in your material.  How do you know when that is?  Do what we did when this large placer first asked all of us for help.  Test your tailing pile with your pan.  

So, how do you break up clay in a small operation? Mix it in a bucket with a small shovel or use a dry wall mixer and a drill in a bucket.  I've done both.  The drill is definitely easier, but if you don't have one or you are not allowed to use anything motorized, a shovel will work.  It can work you to death, too.  LOL!

Gold finished out this week at $1667.60, and we saw DOW 14,009.79, the first time it closed over 14,000 since October 2007.  Hope you are busy getting your equipment ready for this summer.  We will be staying home this year and not attending the Tucson Show in Arizona.  We have this house we bought that needs its’ kitchen fixed.  As Always,

Good Prospecting to You,
Shirley Weilnau
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