You can assume the way it was in the good old days is still true today, and legaly one is not to be expected to work continuously for more than four hours without a 15 min. break. Now you are owed for four and a quarter hours work.
and so on, etc. - To accept or stipulate some other arrangement with your employer may be possable, but could, in some circumstances of employment law, get a bit ambiguous I think.
But anyhow forget all that ! To address your original question scoobysoo, it isn't rocket-science is it ? You've got an eight and a half hour day there. (Eight hours work plus a half hour in the middle for lunch) I'm assuming you're allowed to have a brew in the morning enabling you to slow down to a stop for five minutes or so ; unless you are depended upon to attend a conveyor belt that just does not stop ! If your employer thinks that is a reasonable working condition I'd suggest you leave Siberia 1904 and find another job, simple as.