Popular Minings Mineral Resistance Tester!

[BillNEWAST]

In the Popular Mining Magazine Vol. V Reprint on page 36, is a Mineral Resistance Tester!
The article is by Carl Dahlberg of Bonners Ferry Idaho.

My question for Carl or, anyone with a good grasp of the concept.
Is the below Schematic sufficient to use to measure the resistance of a given volume H2O and Clay?

"WELL I GUESS I'M GETTING TOO OLD TO UPLOAD PNG PICS" can't get it to work!




OR would this one be better?

http://www.tonyvanroon.com/oldwebsite/circ/555dcac.html

I was going to use 2 safety pins as probes mounted on a piece of plastic that would span the mouth of the jar and hold the probes at a fixed distance apart!
Any thoughts suggestions or ????

Sincerely
Bill "Lost Adams"

[WM6]

You can do the same (relative material conductivity/resistance measurement) using this cheap and handy device:

https://www.ebay.co.uk/itm/3-In1-LCD...kAAOSwNZtZyH~u

[BillNEWAST]

WM6, could you please elucidate further on why/how the referenced meter can be used to measure Ohms resistance in ohms with a meter that is calibrated in % moisture???

I'll give some more specs below.

1 - Need to be able to measure resistance in 0-200 ohms, , 201-2000 ohms, 20k-199k ohms, 200k-2000k ohms. This can be accomplished with a Cheap < $10.00 Harbor Freight Cen-Tec multimeter.

2 - You can't use a Straight DC voltage as it will shift over time and won't settle to a stable value! Ala Geophysical Resistivity measurements!

From the article, Carl D. says;

"A method that I chose that is relatively simple and inexpensive is to measure the electrical resistance of soil samples. In most cases soil samples will have a lower resistance near the ore body. ... When measuring resistance a direct current voltage source such as a battery is used along with a sensitive meter for measuring current. ... However, because of the electrochemical nature of an ore body I was getting some erroneous resistance measurements and could not obtain a sastasfactury reading on the ohmmeter. The resistance was changing constantly. There was also some electrodes which was affecting the resistance measurements.
...
I decided to try an arrangement using AC voltage to see if I could get away from some of the problems I had encountered with DC voltage. ... At first I used the AC line voltage as an alternating current source but later used a simple 555 timer circuit that runs off a 9 battery."

I just need to know which of these above circuits would work Best in this application.
I would like to be able to adjust the ac voltage within the circuit to test which voltage is the best to use.

[WM6]

Deciding to AC measurement it is important to which frequency you decide too.

At very high frequency (say 50-100MHz) you can exclude even soil salinity influence to your measurement.

[BillNEWAST]

In further reference to answers, the soil tests will be done as follows;

1- take a soil sample with an auger at the C horizon.
2- screen to -8 mesh minus
3- place 1-2 cups in a plastic Ziploc baggie with some water
4- slosh water to remove the Clay portion of sample
5- pour out water into a pint jar for testing with meter

some variations to the above could be to filter the Clay out of water and then just test the wet clay
BUT at NO time will I be using the METER to test the Resistivity/Resistance of the Ground!!!
Hence the need for the portable hand held meter.

ps The is no Salinity factor in the soil. the soil is a decomposed Black Carboniferous Slate with varying amounts of Sulfides, hence the need to measure resistance.

I hope everyone is able to understand the above. Please if not then ask and I'll try to explain better.
Thanks for you help.
But I am afraid that this thread had digressed far away from the Post and Question.
There is a simple answer in the original post just a PICK of one or the other.
Sincerely
Bill Totally "Lost Adams"

[Carl-NC]

Yes, you need an AC ohmmeter for this, DC won't work well. The 555 timer could be made to do this, but the one you show looks doubtful. Offhand it looks like a connection is missing (pin 6/2 to the RC juction), plus the meter connection looks wrong. The other circuit looks rather useless for what you want. Probably it's gonna take some design effort and a bit of fiddling to make it work.

Or, you can just buy an AC ohmmeter. My B&K RLC meter does impedance (AC ohms) at 100, 1k, and 10k Hz. It's a bit pricey, but I'm guessing there are cheapo models on eBay.

[BillNEWAST]

Thanks Carl!
I was thinking of using a Harbor Freight Cen-Tec multimeter. So this wouldn't work to measure impedance in AC ohms?
So this would be the same problem you run into with a Resistivity Survey set up. Could that set up be used on WET clay/soil samples?

Can you measure Impedance with an Ohm Meter..

https://www.electronicspoint.com/threads/can-you-measure-impedance-with-an-ohm-meter.2126/

I read this article and I think I am beginning to understand.
I'll pursue this more tomorrow as I have to take my younger brother to the hospital in the morning.

Thanks so very much!!
now at least I have an arrow pointing the way

[Carl-NC]

A regular multimeter applies a DC voltage, measures the current, and calculates resistance. What you want is to apply an AC voltage. An "impedance meter" probably does this, as do some LCR meters, but you need to read the fine print. Yes, ground resistivity is a similar problem, but they work by injecting an AC current and measuring the AC voltage.

[BillNEWAST]

Thanks Carl, I have refreshed my one Brain-Sell and have read other post on the I-Net and now I remember why this is a difficult task.
I think I need a Kelvin Resistance meter to do this??? One with double lead probes. One set injects the AC and the others next to it reads the resistance of the Substance under test.
Oh Yea, sorry about trying to send raw pics of the article, I forgot to Shrink the Size and such. Won't happen again till after my next 5 year hiatus.

[Carl-NC]

Kelvin probes are typically used for ground resistivity, but for small samples using voltage mode I think it's not needed.

[BillNEWAST]

Carl here are some (EC) Electrical Conductivity meters I have found on the net.
In your opinion would the cheap ones be good for testing the soil samples and getting a Relative reading between samples? I think I'll get one of the 3-8 dollar ones as I wouldn't be out much if it didn't work, and Boy would it be nice if it did!!!
I know I would have to do a bunch of testing to get a baseline and some semblance of what I am reading on the digital display.

I have a brand new in box Hanna HI98121 pH/ORP & Temp hand held meter. I don't think that ORP would give me a reading I could use to measure the amount of metalic Ions in a clay/soil sample.

https://www.amazon.com/Hanna-Instrum.../dp/B0085WV5BI

https://www.ebay.com/itm/LCD-Digital...wAAOSwX-pZsnOX

https://www.ebay.com/itm/TDS-EC-Mete...tw2caj76u2_lnQ


https://www.ebay.com/itm/Digital-LCD....c100005.m1851

Thanks for your input in advance.
Sincerely
Bill, becoming not so, "Lost Adams"

[Carl-NC]

No idea... I assume a pH meter is the wrong tool, not sure what the others are measuring.

[BillNEWAST]

Carl, here is some more info I found on the I-net.

http://www.octiva.net/projects/ppm/

and cleaned up schematic


Thanks for your input in advance.
Sincerely
Bill, becoming not so, "Lost Adams"

[BillNEWAST]

Hurray Gettin Close!!!

AND

this seems to be most similar to the original PM articles circuit. It's from a MIT 2014 workshop.
https://publiclab.org/wiki/555-conductivity-meter

[BillNEWAST]

Sorry for not updating the thread, but I have been Staking Mining Claims for our local Prospecting Club for over a week now.
I have got lots of reports and links to share on the soil/water tester.
If anyone wants to start Down the Rabbit Hole just Google DIY Electrical Conductivity Meter Circuit.
More later.
Sincerely
Bill "Lost Adams"