In the control room. Darren Dick (Manager of Operations, center) describes computer-automated methods for moving liquid petroleum gas (LPG) into and out of the storage caverns while Scott Case (Facility Manager, at window) weighs in a tanker truck scheduled to receive product (click on the photo for a close-up view of the computer-automated system).

Darrel demonstrates why petroleum gas can be stored as a liquid at high pressures.

A series of valves regulates the injection/extraction of LPG in storage caverns created within the Hutchinson Salt formation. To move LPG into or out of storage, salt brine is injected into or extracted from the caverns.

A few of the seventeen storage cavern wells at the existing facility.

Scott Case (center) discusses the management of brine reserves used in the LPG storage processes. Two, one-million-barrel brine ponds, located within the embankments in the background, are used to store the brine.

A “Class One Injection Well” is used to dispose of excess brine by pumping it into the Ordovician Arbuckle Fm. The well operates under a vaccuum to remove excess brine from the ponds whenever supplies exceed the holding capacities of the ponds or when the brines poses an environmental hazard. (Kurt Shobe, facing group)

Lee Spence (President, Underground Vaults and Storage Inc.) entices one more rider to board the shaft elevator that enters the mine. A 70-second, 650-ft drop is made in total darkness twice a day. Not only is it a dark descent, but the elevator walls are open ("make sure you keep your hats on, and hands, feet, and other objects inside")

Both reluctant and enthusiastic riders don their safety gear.

This "pure salt" sample is part of a salt mining display near the entrance to the mine.

The rock salt mined here is composed predominantly of halite (NaCl) (Click on photo for a close-up view). These crystals will be broken up two or three times before being shipped for commercial use. Rock salt is used in applications ranging from homemade ice cream making to road and sidewalk deicing. It reaches markets as far north as Chicago.

Lee (green hard hat) describes a bulldozer used to excavate salt at the mine face. Pieces of a disassembled "excavator" were imported to the mine via the elevators shown above and the vehicle was reassembled inside the mine. The diesel rig is equipped with scrubbers that "filter" engine exhaust and help to maintain a clean air environment in the mine.

A conveyer belt moves the excavated salt several miles from the mine face to the elevator. The salt passes through at least two crushing hoppers en route to the elevator. At the surface, the salt is cleaned and loaded on trucks or rail cars for shipment.

The rock salt contains clay and algal impurities at some depths giving it a banded or layered appearance.

A plate bolted to the ceiling (top center of picture) is used to measure the annual shrinkage rate of a storage cavern. To monitor possible shrinkage or collapse, a laser device is placed on the floor and shot upward at the plate, measuring the distance from the floor to the ceiling.On average, the ceiling moves only one ten-thousanth of an inch per year. At this rate, it would take about 150,000 years for the ceiling to move downward one inch.