Rosemont Ranch

At the Ranch

Ranchers and Geologists Working Together

Rosemont is a 20,000 acre working cattle ranch about 30 miles south of Tucson, AZ. Rosemont is anticipated to have one of our country's largest unmined copper, molybdenum and silver deposits.


Tom Kay

Tom Kay

After approximately 20 years on their ranch in the Four Corners region near Mesa Verde, Colorado, Tom Kay and his wife Dena decided to return to Arizona to be closer to family. The Kays now call the 13,000-acre Jarillas Ranch with its solar-powered ranch house in Arivaca home.

Originally from Easton, Pennsylvania, Tom's family moved to Tucson in the 1940's, for the health benefits of the dry, Sonoran climate and built a restaurant and motel at Pina Blanca Lake in the 50's. As an adult, Tom went on to have multiple businesses, from vacuum machinery to a sign company and athletic clubs, but his true love has always been ranching.

"You've got to love being a cowboy. You don't do it for the money. No day's the same when you're working with the cattle, fixing fences, fixing a truck, whatever needs to be done to keep the ranch running smoothly. I was involved back before a lot of the work that's been done in the region. We've got to have copper, so we might as well find ways for this to be a win-win for all involved. We need copper, but we don't need to tear everything up in the process. This is going to be a working ranch throughout. I respect their vision, their approach, their plans. I'm enthusiastic."

Rosemont Ranch Geology Exploration

Karl Weiss

Karl at the Weather Station

After retiring from a career in intelligence in the United States Air Force, Karl Weiss worked in computer networking, for the Salvation Army, as a carpenter, and for a bowling alley. With degrees in geology and information resources from the University of Texas and the University of Arizona, respectively, he now works for Rosemont Ranch as a database administrator. In this photo, he is monitoring the on-site weather station as part of the permitting process.

Augusta Research Corporation monitors temperature, humidity, particulates, and other environmental indicators to understand the potential effects of ongoing operations on baseline ambient air quality. Kar's wife, Leah Sandwell-Weiss, is a retired Air Force Judge Advocate, now on faculty at the University of Arizona Rogers College of Law.

Dave Briggs


Dave Briggs, originally from Richmond, earned his geology degree from Virginia Tech, and moved to Tucson in 1977. He specializes in the geotechnical work required on the conveyor belt where all of the core samples must be wet down, analyzed, and described by someone with an expert eye. Alone, Dave can analyze and process approximately 200-300 feet of core sample per day, but he often works in conjunction with a team of geologists.

Core Drill

Core Drilling

The sampling team runs a brand new Boart Longyear LF90D drill rig, extracting core samples using a hydraulic-pressured rig equipped with a diamond drill bit. All drilling fluids are biodegradable, and all sites and drilling pads are reclaimed once exploration is completed.

Cutting Samples

Cutting Samples

Testing is then conducted on rock mechanics and technical details of the core samples are logged immediately after extraction. Using an Easymark tool and Call & Nicholas equipment, the core is aligned, fractures measured, and angles examined to understand how faults are oriented on the rock. The team at Rosemont is working to understand the rock's depth, slope, sturdiness, and various other features that will factor into the planning process for eventual pit slope and design.

All core samples collected at the site are photographed, logged, cut, palletized, and organized before being sent to labs in Tucson, such as Mountain States Testing Laboratories and Skyline Laboratories for chemical and metallurgical analysis.