We run drones to perform surveys at a mine in Laos. Thankfully there are no government imposed flight restriction within the mine area, although of course we follow safe guidelines, stay well away from people and blasts and generally have had a very good run with high quality surveys being collected. A few weeks ago however, we had an usual flight which ended up with a written off drone. The pilot claims that near the start of his flight, his ipad went black. He hit the RTH button on the remote and waited, about 5 minutes later the controller turned-itself off and the drone never returned. Using the map, he located the drone which has sustained significant damage, of note is that the battery was found about 10m away from the drone. We use GSP with fully pre-programmed flight paths. From the flight logs (attached and linked below), I can see a rapid forward flight showing in the horizontal speed starting 1 min 24.7 seconds into the flight with accompanying pitch change, then the log stops. Battery condition was fine. My guess is that the battery became disconnected mid-air but would really appreciate some experts looking at the log to see if I am missing anything. Thanks for your time!