El Malpais: Xenolith Cave, Feb 2017 · Index · Fort Stanton Cave, May 2017

Trip Report: Millrace Cave, March 5th, 2017

NMT Caving Club,

Trip leader: David Hunter

Attending: Connor, Amy, Tyler, and Eshani

Back in the late 90's and early 2000's Millrace was a common stop for the NMT Caving Club as the BLM managed the cave and was was not very restrictive about access. But then a resurvey of the land put the entry to Millrace a few feet onto private property. So the BLM stopped giving permission for entry as entry was no longer their property. I was recently able to get contact information for the land manager and obtain permission to cross their land and enter the cave. The only condition was that everybody sign a waiver promising to hold them harmless.

Millrace cave is a gypsum cave that is carved out where an arroyo flows under an old lava flow. Long ago the lava obstructed the water path and solidified into a rather substantial barrier. Instead of pooling and flowing over, the water simply started cutting through the gypsum below. The result is a series of narrow channels that quickly descend to the presumed water table.

After dropping off the requested waiver, the group parked near the cave and got ready to to.

At the cars and ready to head over to the cave.

The entry to Millrace cave is a short climb down. As this is the drain for an arroyo it is critical to check the weather forecast prior to entry. DO NOT enter the cave if there is a chance of rain. While a light rain might not cause the cave to flood a heavy rain - anywhere in the upstream drainage area - could be fatal. I am not going to bet my life on what the weather man says will be a light rain actually being light...

The entry to Millrace cave.

While the old lava flow seems to have forced the water underground, once underground the passage quickly drops deep into the gypsum layer. Shown here is one of the numerous climb downs. While the group was able to handle many of them, several were deemed beyond the experience of the beginners.

One of the many climb downs in Millrace.

One drop off was at over 10ft and would have required a rope to get down. We later learned that there is a passage around this drop off. One day we need to find that passage. Or return with a vertically trained crew and suitable gear.

A large drop off in Millrace Cave.

This cave also suffers from vandalism. The location is fairly well known and many people enter without bothering to contact the landowner. On our way out we encountered a couple spelunkers which, much to our surprise, brought a dog with them. They seemed to be polite and well behaved so we suggested that they consider using helmets, always bring 3 sources of light, and be sure to contact the landowner prior to entry. We also pointed them to caves.org to find an organized NSS grotto. Sadly, other spulnkers have done damage such as what is shown here. This might wear away with future floods, or it might be above the flood line. There was also some garbage of which we removed.

Some scratches carved into the wall.

Connor earned the best expression of the trip award.

Connor's expression

As usual, Eshani earned the Happy Caver award.

Eshani inside Millrace Cave.

The group made it to the end of one of the passages. The various forks of the cave all terminate in either mud or water, and at about the same level. It appears that on the passage reaches the water table it seeps into the rock and the passage peters out.

The pool at the end of one of the passages.

There are some crystals in the wall. While neat, they are not much by the standards of New Mexico caves.

Some crystals in the wall of Millrace.

As usual, after the trip we returned to Socorro to clean and decon the gear.

El Malpais: Xenolith Cave, Feb 2017 · Index · Fort Stanton Cave, May 2017

Last Updated: June 2017; Original Posting.

Writeup and first two photos, © David C. Hunter, 2017
Large drop and happy Eshani photo, © Connor Whitman, 2017
All other photos, © Eshani Hettiarachchi, 2017

nmtcaver {at) dragonsdawn (dot] org

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