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Beautiful Landscape

Our Mission

Our mission is to offer a resistivity and induced polarization instrument that is rugged and lightweight for use in a wide variety of settings, at an affordable price when compared to other geophysical instruments on the market.  We support the individual geophysical contractors, as well as larger teams from major exploration organizations, departments and companies.


"We at Exploration Instruments have offered various models of the MiniRes, built by L&R Instruments, in our rental inventory since our first days of business over 12 years ago. The quality of the engineering in this instrument is excellent and I continue to be impressed with the range of applications for which it can be used. We experience virtually 100% uptime when it is in the field. For accuracy, repeatability and ease of use, I would rank it among the best available anywhere today."


Dennis Mills


Exploration Instruments LLC

"In "2001", I rented a MiniRes from "Exploration Instruments" and was so impressed that I bought one for use in my consulting business. Since then, my work has all been facilitated by using the MiniRes and ULTRA MiniRes Instruments to carry out Hydro Geophysical Investigations to locate water wells in fracture zones in New Jersey and recently for the Washington Township Municipal Utility Authority. My results are on the surface and within wells. I gave a presentation regarding my success with using the ULTRA MiniRes at the "National Ground Water Association 2008 Summit" and to the New Jersey State Geological Survey. I am a champion of this efficient flexible instrument, especially it's IP ability. I think the MiniRes instruments would be great for maximizing water resources in 3rd world countries."


Anthony M. Hauck III, GpE, MSc

Consulting Geophysicist

AB Dartmoth College

GpE Colorado School of Mines

Masters Degree (SM) MIT

Chief Geophysicist Phelps Dodge 22 years



John Fett was a consultant, running his own small geophysical business for the first half of his career.  He also built an instrument rental business, before deciding to purchase LaCoste and Romberg. 

His daughter, Phyllis, worked with him on a variety of projects, and also consulted as a geophysicist between jobs.  She has a B.S. in Geophysical Engineering from Colorado School of Mines and a Master of Science in Geosciences, specializing in Geophysics, from University of Arizona in Tucson. She has worked as a Sensor System Analyst for Martin Marietta, a staff Geophysicist for Newmont Exploration, a staff Geophysicist for USGS, and a substitute teacher in a small farming community.

Byron Arnasson, the Chief Scientist who worked with John Fett on the development of the MiniRes designs, has degrees from University of Utah, and decades of experience with both doing geophysical field surveys and designing the equipment for those surveys. His experience includes doing magnetotelluric surveys, so he has a deep understanding of the earth's response to electrical currents, as well as the theory associated with measuring resistivity and induced polarization.  Byron continues to oversee the Ultra MiniRes design and production, and is part owner of

L and R Instruments. Byron also advises customers as they use the instrument in a wide variety of survey environments, for a wide variety of applications.

John's daughter, Elise, and Rob Lober, manage L and R Instruments.  Rob is the sales and production manager.  They are located in Nevada, and are the first contacts for any business, questions, orders, feedback, etc.  Elise has experience with running her own Architecture and Engineering business, and Rob has both a business degree and experience with running a wide variety of businesses, including electronics and repair services for complex mechanical systems. Rob responds to new orders, requests for repairs, invoicing, etc. and coordinates with Rick, the lead technician for building and repairing instruments.

Like Phyllis, Elise helped her father with field surveys when she was young, and worked with both Byron and Phyllis after John's death, to demo and present the MiniRes products.  She redesigned production labs and office spaces for LaCoste and Romberg, when they moved to a larger building in the '80's. She is currently the company CEO.


Experienced Leadership

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