My Minelab metal detector has a prospecting mode built in that is selectable when you wish to find metal such as gold nuggets and relics in highly mineralised areas.
When used in prospecting mode, the targets are identified by audio only, and the number shown on the display is not releated to the target, instead it shows the Iron Mask value, as does the Discrimination Scale.
In the prospecting mode the detector becomes more sensitive to small target signals.
The numerals (Iron Mask Level) and the segmented scale (Iron Mask Discrimination Scale) are used to identify the amount of iron signals being rejected by the detector.
Enough talk, let's get that coil on the ground!
Click on the photo for a closer look.....