There has been renewed activity in creating updated section maps for Carlsbad Cavern over the past few years. This has included a number of trips to correct data errors, resketch areas with detail or accuracy problems, and push leads. I attended my first expedition in 2012 and on the very first mop-up survey trip near the Lunch Room, Bob Osburn and I discovered a virgin 300' long canyon passage that loops between Appetite Hill and the elevators.
In February of this year a team including Roger Harris, Garrett Jorgensen, Kevin Manley and myself conducted a resurvey of Spirit World - in the ceiling of the Big Room.
http://www.nps.gov/cave/planyourvisit/upload/chu_20031215.pdf
Near the back of Spirit World is an alcove in the ceiling, 30' above, that was a possible lead. Roger and I led a bolt climb to this alcove, but it turned out to be blind. 100 feet north of this lead is a high ledge, about 20' above the floor, that was another potential lead, but we didn't have the time or energy to make the climb.
In July Pete Johnson, Kevin Manley and I followed a lead out of the Grand Ballroom (below the Guadalupe Room) and climbed into virgin passage dubbed "Spooky Chimney". The exploration of this area was continued last week with help from Shawn Thomas, Joyce Hoffmaster and Stan Allison where passage measuring 20' high and wide was surveyed. Several leads remain in this area, which is located directly under Hall of the White Giant.
Shawn Thomas and I returned to Spirit World on Halloween to check the 20' ledge lead off the list. This climb was made using a combination of rope trickery, an aid move off a bolt, and an exciting aid to free climbing transition. At the top of the ledge, to our surprise, was a passage leading off to the SW with a flowstone and popcorn floor. At the end of this passage is a large room that is roughly 100 feet in diameter and averaging 20 feet high. At the far end of the room is a promising dome climb and other possible leads. We believe this room, Halloween Hall, may be the largest found in Carlsbad Cavern since the Guadalupe Room discovery in 1966.