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

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This image shows the final mounting work of the middle adit of the Grandview mine. Excess steel is trimmed off with the torch, and mounting pins are welded to the gate frame. The outside edge of the frame is checked for gaps along the adit wall, and extra steel braces are welded in place as needed. Any rough edges near the bat flyway gaps between the bars are ground smooth. Rough and sharp edges on a bat gate can tear bat wings as they fly through the portal.

This adit had a variety of historical artifacts in the tunnel. These included a functioning ore car that rolled freely along the narrow gauge rails. We moved this car foward out of the deep mine so that visitors could view the car from behind the locked gate. We also placed a historic digging pick and digging bar next to this mine car. During bat surveys we found the remnants of a burlap sack with the lettering "G V Hotel" stenciled on the side. This sack is from the Grandview Hotel that was located at Grandview Point above the mesa. In the early days of grand canyon visitation, this hotel was a very popular spot. Many tourists would stay at the Grandview Hotel and hike down to the mine workings of the Horseshoe Mesa. Many historic signatures from the turn of the century can be found on walls throughout the mesa.

Since this mine had a high amount of copper, many interesting copper based minerals have been found at this site such as Malachite and Azurite. As you walk around the mine workings watch the ground for blue rocks. This is Azurite which the miners would look for as an indicator of weathered copper sulfide ores. The green rock is Malachite and is another good clue for the miner on where to dig for copper ore.


Bat Gate Mounting


Culvert Gate with Historic Shoring Timbers


This photo is the final view of the upper adit of the Grandview mine. The original entrance shoring timbers of this mine have been rebuilt over the culvert entrance. The excess timbers are stacked outside as if ready for a 1900's shoring project. The 30 inch culvert will provide stability for the collapsing entrance, and ensure a portal for the Townsend's Long-eared bat colony using this entrance to the mine. To avoid later infilling, the entry path leading up to this portal has been dug down in a sloping manner so that water drainage flows away from the entrance.

Further reading about the history and geology of these mines can be found in these excelent books:

Quest for the Pillar of Gold, Billingsly, 1997
Hiking the Grand Canyon's Geology, Abbott, 2004


This view is of the final gate in the middle adit of the Grandview Mine. Note the heavy lock box on the left side of the gate, and the customized outer frame contouring the tunnel walls. Installation of all three gates were completed in over one weekend to minimize impact to the park.
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Funding for this project was generously donated by the mining company Freeport McMoRan, the largest copper mining company in the world. Further support was offered by bat biologist Jason Corbett of BCI (Bat Conservation International). Original bat surveys conducted by Dr. Scott Altenchach brought awareness to this import site. Helicopter support & general guidance was offered by hydrologist and mine resource manager Steve Rice, and many others from the GCNP (Grand Canyon National Park). The project was managed by Tom Gilleland of MineGates, Inc. The skilled gate building and installation team include Bruce Lynn, John Norman, JD Mizer, Larry Zimmer, Doug Billings, Jason Knight, Bob Goforth, Matt Love, and Ben Sainsbury.

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Grandview and Last Chance Mine Bat Gate Project


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Finished Bat Gate in Grandview Mine


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