Appendix N

Comparison of Terrameter with MiniRes

Like the ABEM Terrameter, nearly all other competitive reistivity meters use the TIME DOMAIN mode of operating. We respect the choice of our honorable and competent Swedish competitors.

The MiniRes uses the FREQUENCY DOMAIN for resistivity and the PHASE DOMAIN FOR IP. The PHASE DOMAIN method of measuring IP, In our opinion, is MUCH better than the TIME DOMAIN method of measuring IP. The PHASE DOMAIN IP method records at the same time as it transmits. This gives the PHASE mode a tremendous energy efficiency advantage over the TIME DOMAIN IP method which records only after the transmitter is turned off/

The Terrameter displays the resistivity at the end of each reading and after a pre-specified number of readings it displays and holds that averaged reading. The MiniRes is constantly displaying the real-time values. If they are wandering, the observer can do a good job of averaging them. If there is an excursion due to local lightning, the observer of the MiniRes can disregard that observation. The Terrameter observer would probably be unaware of the noise level of the site.

"A" Spacing in Feet

· A is the “A” spacing in the Wenner electrode array

· B is the apparent resistivity in Ohm-Meters from the MiniRes

· C is the actual meter reading from the MiniRes

· D is the apparent resistivity in Ohm-Meters from the Terrameter

· E is the actual meter reading from the Terrameter

The data points virtually fall on top of each other. The “Super” MiniRes obtains reliable data with 1,800 feet (600 meters) between current electrodes. MiniRes current is 10 milliamp

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