I believe Old Sump Shaft now lies under the decking constructed in front of 'Victory Heights', the house converted from an old Water Board building some years ago.
The main shafts of Trenwith Mine are Wills, Victory, Berrimans, Old Sump (also called Town Shaft), Allotment Shaft and Dales Shaft. There is also an unnamed shaft at Trenwith Terrace. (It opened up some years ago in someone's kitchen!). In order to supply St. Ives with a regular supply of water, a submersible pump was installed in Victory Shaft 123 feet below ordnance datum (approx. 383 feet from surface) in 1948. There were also centrifugal pumps installed in Old Sump (Town Shaft), approx. 100 feet from surface. These fed a rising main which transferred water to a reservoir built near Knills Steeple on Worvas Hill in 1932, which supplied water to Carbis Bay and Lelant. A dam and penstock was installed in the deep adit near Dales Shaft. From here water was transferred to supply St. Ives via a 6" gravity main through deep adit which originally emptied behind the Royal Cinema.
Deep adit runs from Rosewall Hill, through the old setts of St. Ives Consols and Trenwith. The only connection between Consols and Trenwith is this deep adit. Shallow adit ran from Rosewall Hill, through Consols and emptied at Nanjivey Terrace, near the British Legion. Launders placed at shallow adit level in Cornish Shaft to convey water over the shaft and through to the Nanjivey portal were found to have broken down by 1948, so all water from shallow adit here descends to deep adit.
Previous to St. Ives Borough Council supplying the town with Trenwith water, they got a supply from the adit at Wheal Allen. The site of this mine, near St. Ives Consols, was marked by a tall, solitary chimney in the fields at Hellesveor. I say "was" because the chimney collapsed into a heap of rubble last week!