Monitoring surfactant content to control hot water process for tar sand

The present invention is based on the following: (1) that when tar sand is conditioned and diluted in the hot water extraction process, there are two classes of anionic surfactants (originating from carboxylate and sulfonate groups) present in the process water; (2) that each of these surfactants has the potential to dominantly influence the maximizing of primary froth production by the process; (3) that it is possible for a particular extraction circuit to determine the critical free surfactant concentration in the process water at which primary froth extraction is maximized for each of the two classes of surfactant; (4) and that it is possible to determine which of the two classes of surfactant will first (that is, at lowest NaOH addition) dominate the process when a particular tar sand feed is being processed. The present invention therefore involves: determining the critical free surfactant concentrations ("C.sub.cs.sup.O " and "C.sub.ss.sup.O ") for the circuit for each of the carboxylate and sulfonate classes of surfactants; monitoring the free surfactant concentrations ("C.sub.cs " and "C.sub.ss ") in the process water for an ore being processed; determining which of C.sub.cs.sup.O and C.sub.SS.sup.O occurs at a lower NaOH addition; and then adjusting NaOH addition to the extraction process to bring the first dominating surfactant concentration toward the critical concentration value.