Fire Assay best to determine ore value?

[dustyboots]

Found an area of mine dumps from small pocket mines that when sampled seems to have quite a bit of fine free milling gold 30-40 colors to the bucket. Is a fire assay the best way to get an idea of the ore value. The area has no water near by and it is not feasible to move the ore so I think the only efficient way to process would be with a drywasher. Thanks in advance for any help

 

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[Assembler]

Hello
Should be able to crush and hand stamp into powder then hand pan (Dry or wet) to get a good idea of value. However is time consuming for the number of colors per bucket. Maybe a Falcon metal detector may show some of the rock being better then the other rocks? Maybe a 4 inch coil on a gold detector may also be used to help sort out rocks if looking for 'Pockets'?

 

[Eu_citzen]

If you have free mill gold you can crush and test it yourself. Note weight of crushed ore and weight of gold you got from it.
Fire assay is good for more accurate tests.
However no assay method will be better then the samples you test.

A "grab sample" (= 1 fist sized rock sample) is not very accurate. It's used more or less as a indication.
Better is to send several small rock samples.

 

[Assembler]

Hello
What is the hardness and type of rock in question? A impact mill may work to speed up the sample process?

 

[dustyboots]

I believe the host rock was quartz along a shale contact zone. I did some additional sampling and was getting 20-30 colors per pan withough doing any ore crushing. I also think that the original miners were only going after the quartz and visible gold which was taken off site to be processed. There is some small quartz still on site but most I believe was hauled to another location to be processed.

 

[Assembler]

Contact zone.

Hello
Sounds like most of the quartz is removed. Wise to sample crush and pan the contact zone material. what ever it mite be for the colors. May not hurt to also use a pinpoint MD such as a Falcon as well to help out. The colors could be 'Float gold' that came from the removal of the quarts?
More samples should help pinpoint where the 'Colors' are coming from. If you can find colors in the contact zone material you may be on to something.

 

[Assembler]

Hello
By any chance is there any disruptive veins or shoots protruding through any of the shale contact zone? If there is you may want to run the pinpoint MD Falcon along these veins of minerals to start to see the better spots to then crush and pan for the best value. The best 'Detector is in one's head'.
The rest of the 'Contact zone' may not be very good just have to keep testing. When you have a few tons collected this one will be ready to maybe crush and pan for you? Still putting time and money into the sink hole of a jaw crusher.....LOL

 

[911Met]

Ever did your fire assays in a microwave oven https://www.911metallurgist.com/diy-fire-assay-home-laboratory/