We have ninety minutes to carry the concrete from the mixing plant to the worksite.
I think “tempat pengerjaan” is a typo. “Tempat kerja” is the standard expression for a “workplace”. “Pengerjaan” (root = kerja) means “working” or “executing” (i.e. the process of action).
Just in case, I looked up “pengerjaan” in LCC, but "tempat’ doesn’t rank in the top 50th. Google Images returns only pictures of electrical devices.