Bright starlike object over oil refinery in SLC zig zag over mountainside & went straight up at high speed

Late July or early August,saw a bright starlite directly over oil refinery just north of SLC. The light(white in color)then zig zagged North to South about one mile in legnth over the mountainside just east of the oil refinery. it did so in about 2 seconds.it then went straight up in the sky at an extremely high speed. I was with two friends sitting in a car and they saw it also.we looked at each other in disbelief & said "Did you see that?".it was almost as if our attention was drawn to it as soon as it appeared over the refinery.we were only 3-4 miles away from the object so it probably was about the size of a car. it just seemed like a very bright star. I would like to know if anyone else had seen this. I realize it is an old report.
Date is approximate.  We have arbitrarily assigned a date in July 1980 so that the report sorts to that date.  PD