Yesterday while descending Pandora’s Box we stuck a rope while using a Smooth Operator on the second rappel. We’ve been using this particular setup for years (and hundreds of rappels) without incident so for us this failure was significant. Our gear/setup: To pull the Smooth Operator we use a 2mm Dyneema cord (arborist throw line). We like how lightweight and compactable it is. We can squeeze 300ft into a tiny bag that can easily hang off of a harness or fit in pack. We also use 2 carabineers tied together with cordage of some kind (basically a homemade quick draw) to lock off the system for all but the last person. What Happened: The anchor for the second rappel in Pandora’s Box is webbing from a log jam extended approximately 1 foot over the ledge. The rappel is generally 2 stage but optionally done as 2 separate rappels if there is material for a deadman in the middle section. The rappel is notorious for sticking ropes which is why the anchor is extended so far over the ledge. We opted to rig our fiddlestick on the established anchor but to shorten it for a “courtesy” for everybody but the last person. The drawback of this decision is we weren’t able to witness how the Smooth Operator would “float” prior to the last person which is a huge benefit to using the Smooth Operator over other similar devices. The first 4 in our group went over without incident. I was second to last and before I went I mentioned to the last man that the stone knot looked unusual (more long and skinny than short and fat). The stone knot being dressed incorrectly could have been the source of our challenges. Being second to last it was my job to manage the pull cord. I opted to stop in the middle stage of the rappel in order to more safely belay the last man and also manage the pull cord. I threw the pull cord/bag down the second stage to be secured RDC in an ideal pulling position. The last person made the awkward transition, pulled the safety “quickdraw” and set the smooth operator in what looked like a free floating, ideal position. Both of us observed that the pull cord was in an ideal position before rappelling down the second stage. Our problems began when we tried to pull the cord from the RDC position. Wouldn’t budge. We then moved the pull cord LDC. LDC put the pull cord in much more contact with rock but gave us more options to get leverage to pull. Wouldn’t budge. Eventually one of us stemmed up into the canyon, tied into the pull cord and fully weighted it. Wouldn’t budge. On the next try 2 of us weighted the pull cord for a combined 350 lbs. Snap! The pull cord broke and we tumbled to the ground. What was left of the cord snapped back out of reach. The cord should have been able to hold 1000 lbs so it either isn’t as strong as rated or was cut on some sharp rock from the less than ideal LDC pull spot. To resolve the situation one of our group ascended all the way back up to the Smooth Operator to find the pull cord wrapped around the stick (photo attached). He unwrapped it (leaving the original stone knot), rappelled down and pulled (with much effort) the stick from the middle station. He then used the deadman from the middle station to finish the pitch. We aren’t sure exactly what went wrong. The stone knot could have been incorrectly dressed and after weighting the rope made the stick impossible to pull. The pull cord could have somehow twisted around the stick when we moved LDC to try a second pull. Or the pull cord could have looped around the stick from the recoil when the cord broke. Photos: The first photo is a closeup of the stick after ascending the rope to find the pull cord looped over the stick. The second photo is of the rigging with the Smooth Operator locked off (with "quickdraw") and the "courtesy" shortening of the anchor in place.