This is a section of the water race that brought water to the turbine and to the pumps (if there were four as described) for operating the monitors that directed powerful jets of water at the gravel faces in which the gold was found. with a short supply of water in the river (it is not a big river) one might expect that the pumps were in the turbine tailrace so as to only use water for sluicing after it had been through the turbine to extract pumping energy - but unless photos turn up I guess we will not know the layout. You can see the wide wooden pulley out to the left of the pump. It would have used flat belts and getting these belts (and paying for them) was clearly an issue for the Tamati Gold Mining Company. It is recorded in newspapers of the time as being something they struggled with and when the company was wound up, the value of belts in stock was a factor in the summation of the company assets.