Measuring moisture in magnetic material?

Hi Robert, by measuring moisture content are you referring to the water content of mined ore? There should be many ways to measure that quickly regardless of the magnetic qualities. If only a relativistic measurement is needed, maybe try taking a kilo of material, spread it over a big pan, and heat to 150 degrees Celsius. Measure how long it takes for the pan to exceed 100 degrees and that relates to how much water was present. Obviously that's not an accurate measurement but if you needed something more precise try capturing those vapors and condensing into liquid water. Or perhaps measure conductivity. Or specific gravity. Or energy consumed to solidify by freezing. Or absorption of microwave energy, etc...

That could work if you can electrically isolate two metal "side boards" on a conveyor belt. At least that method worked like a champ on my railroad signal track circuits. I could tell you how wet the track was by what my "track voltages" were. :)
Alvin in AZ (retired signal-ape)