How we read a haul cycle from paper shift sheets
Most Vietnamese quarries still close a shift with a paper sheet: loads, destination, delays, and a signature. We start there, not with a blank spreadsheet. The first pass is simply to sit with the shift boss and ask what each abbreviation means on that particular site. “Chờ” may mean waiting at the shovel, waiting at the crusher, or waiting for a blast. Mixing those three ruins any later chart.
Once the codes are agreed, we count loads against the known truck body size and the density the surveyor last used. That gives a tonne estimate the plant can compare with the weighbridge. If the two disagree by more than a few percent, we go back to the bench rather than forcing the numbers to match.
The cycle chart is then a simple sequence: spot, load, travel loaded, dump, travel empty. We do not invent missing segments. If the sheet only records load and dump times, the travel is shown as a gap, not a guess. Superintendents prefer an honest gap to a pretty line that nobody remembers from the road.
We keep the original sheets. When a later argument starts about a rainy Thursday in Binh Thuan, the paper is still in the folder. Charts are a reading of the record, not a replacement for it.