HOIST WAS BEING OPERATED WITH 3 MEN DOING MAINTENANCE WITHIN THE SHAFT. HEAVY RAIN WAS FALLING. RUNOFF EVENTUALLY OVERCAME THE DITCHING AROUND BUILDINGS. WATER FLOODED INTO A STORAGE BLDG., INTO AN OLD CABLEWAY IN THE FLOOR, THROUGH CONDUIT INTO AN ACTIVE MANHOLE, THROUGH CONDUIT INTO THE HOIST BLDG. & FLOODED THE BASEMENT PIT.