so you need to know that
1pound=16ounches
1oz=1ounce
1ton=2000pounds=2000 times 16=32000oz
therefor just divide
134893oz/16=pounds=8430 and 13/16 pounds or 8430.8125 pounds
to find tons, just divide the pounds by 2000
8430.8125/2000=4.21541 tons
134893oz=8430.8125 pounds=4.21541 tons