BATCHING AND MIXING
2301.3F1 states that when m ixing opera tions are first starte d on a project, set th e timing device to produce an operating cycle of 75 seconds for single drum and 55 seconds for dual drum mixers. See Figure C 5-694.410 for an example of a single drum mixer and Figure D 5-694.410 for an example of a dual drum mixer.