Grandview and Last Chance Mines Gating Project
Horseshoe Mesa, Grand Canyon National Park

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GCNP provided Helicopter support for ferrying the gates, tools and equipment to this remote site. The expert skills of our helicopter pilot and the professionalism of the helicopter support crew greatly helped our group get this project completed ahead of schedule. Our helicopter pilot was able to deliver the camp load and the upper Grandview adit load easily.

The middle Grandview adit and the lower Last Chance adit were much more challenging. These adits were situated mid-cliff and only had flat target areas of about 8 feet wide trails right next to the cliff. The helicopter was able to hover very near the cliff wall and place these cargo nets and gates right on target. One or two feet off and our gear would be bouncing down the canyon, but the helicopter pilot is an expert and our gear arrived safely. This successful delivery also shortened our schedule as we had originally planned to drop all our gear and gates on top of the mesa and lower it over the edge by roped haul systems.


Helicopter Hauling Equipment to Last Chance Adit


Trimming Bat Gate


Once the gates and tools are onsite, each team would fit the gate to it's specific location in the adit. Normally the gate would need to be trimmed or expanded depending on the adit walls. Trimming is done with the "portable" cutting torch as shown in the photo. When our middle Grandview mine adit torch broke, we had to shuttle this 70 pound "portable" cutting torch up from the lower Last Chance Adit. Fortunately, we planned ahead and brought along backup tools. Depending on the airflow of the adit, sometimes it is best to do torch trimming work outside of the tunnel.

Large gates such as this one require two to three workers to manuever the gate into place. The hammer drill used for drilling holes for the mounting pins, also acted as a chissel for widening spots along the adit walls. Large prybars and light sledehammers are also useful pursuading the gate into it's final position.


After the gates are fitted at their specific location in the adit tunnel, the walls are marked for the mounting pins. In this picture we are drilling one inch holes that will hold the mounting pins for the gate. These 12 inch long pins are then pounded into the wall and later clamped and welded to the gate. Much longer pins are placed into the floor and are also welded to tabs on the base of the gate.

Note the safety gear worn by the driller. Any underground work requires the use of approved caving helmets with mounted lights. Safety glasses, respirator and high traction boots are standard gear for this project. Each of our team members are vertical cavers with Grand Canyon experience. Additional training included MSHA mine safety training, NCRC cave rescue, BCI mine gating training, and Bat Gate installation experience.

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Drilling Holes for Steel Mounting Pins


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