Geophysics in mining exploration focuses on electrical methods. Kenneth Zonge has been one of the leaders in the development of electrical prospecting techniques and technology. Under his leadership, Zonge Engineering and Research (not to be confused with or compared to the large geophysical R&D corporations in seismic methods) has quietly and steadily made a place for itself in the technical community through the design and development of electrical equipment for mineral exploration as well as in engineering and environmental sciences.
     Kenneth's doctoral research and dissertation at the University of Arizona (1972) in complex resistivity was directed toward a means to identify specific minerals using electrical techniques. Zonge Engineering was formed shortly thereafter to continue this research approach with the intent of applying the techniques to field exploration. In the following years this ongoing research in complex resistivity was widely reviewed and discussed. Although the particular approach to mineral discrimination was not then a commercially successful venture, the early work evolved into a new approach and practical field system for induced polarization surveys.
     Another side benefit was the development of a relatively simple and practical solution to remove the spurious and contaminating effects of electromagnetics (EM) coupling, which arise from the geometry of the ordinary induced polarization (IP) measuring technique. Kenneth was one of the first to routinely decouple the IP response from the EM coupling effects.
     In later years he expanded into other electrical exploration technologies. Kenneth was in the forefront of the development of the controlled source audiomagnetotelluric (CSAMT) technique and a strong proponent of its use for exploration of deeply buried targets.
     Zonge Engineering and Research has grown from a small group of four dedicated individuals to more than 60 full-time employees worldwide who handle equipment development, sales and service, and field applications. More than 12 field crews operate from offices in Tucson, Adelaide, Reno, Hermosillo and Fairbanks (during the field season).
     In 1978, the company initiated a complete line of transmitters, receivers, and peripheral equipment used for many types of electrical surveys. That integrated approach persists today. With advances in microprocessor technology, the latest receiver is a multichannel, multipurpose system with 32-bit microprocessor technology which can run resistivity/IP, CSAMT, TEM, AMT, and MT programs without internal hardware configuration changes. This latest version, the GPD-32 receiver, is lighter, faster, and more efficient than its predecessors and is a versatile, compact, sophisticated but utilitarian, digital acquisition system. Currently 200 of these systems are being used worldwide.
     The primary activity of Zonge Engineering and Research has been related to mining exploration clients. A steadily growing segment is environmental science in which electrical mapping of subsurface structure and contamination plumes are important functions. And occasionally, specific but limited applications in hydrocarbon exploration are recognized.
     In the many years I have known Ken, he has always been the epitome of a quiet, dedicated, hard-working scientist and engineer, and always a gentleman. Despite financial ups and downs, he has endured, and his company has flourished on selling to a demanding industry with its own internal drawbacks in budget and geophysical exploration program continuity. These difficulties have not deterred Ken from maintaining his vision of an increasingly sophisticated and multipurpose electrical acquisition system for field use. His quiet leadership has persevered, and his company maintains a status in the vanguard of those in the manufacture and widespread use of electrical method systems that are considered by many to be the state of the art in the commercial world.
     Ken is dedicated to his family and his work. He has served the mineral exploration and environmental science communities well, not only as a supplier of hardware but also as a source of technical information through both his publications and his willingness to share his expertise as an able and patient teacher.
     If success is measured less by cash flow than by the amount of recognition and respect received from friends, colleagues, competitors, and other exploration and engineering companies, then Zonge Engineering is indeed successful, and Ken himself is a giant in his chosen field.

      Jack Corbett