tooele, object over mouantains disapears.i have to preface this with a brief discription of my job duties. i work security at an army depot where we process and store munitions,(no area 51 type stuff here), we check i.d.'s for entry, escort semi trucks carrying ammunition, and do checks on buildings and storage bunckers (igloos) after hours. this happened on mon. oct. 15th. from 5:45-5:50 p.m., i was in the ammunition are doing checks on igloos when i noticed the sun glint off of something out of the corner of my eye. it was an oblong object moving slowly to the south west toward some mouantains. i looked at for a few seconds, didn't see wings, as there is an airport not far away, outside of salt lake city, i thought maybe it was an airplane and continued my checks. i went on to about 2 more igloos when i noticed this object glint off the sun again, this time i stopped to look at it because it seemed to be very low, barley above the mouantains it was moving toward, and slow for an airplaine. at one! point it seemed to stop, then "jump" forward like manual transmission car out of gear. it seemed to fade out,back in again, jump, then fade out and disapeer. there were some clouds coming up over the mouantain but this object was higher than them and had not gotten to them yet. i can't explain the "jumping" or fading out. i saw no wings on it and it kind of looked like a low flying blimp. i wish i'd have checked out binoculars from roll call, then i could have seen it more clearly. i see planes fly in the area all the time, but haven't seen anything like this before.