Abstract: A system for heap leach mining comprises supply and header pipes for conducting a leaching solution alongside a bed or "heap" of crushed metal-laden ore deposited on an impervious pad. A series of spaced tubes are connected to the supply and header pipes to extend transversely thereof, over the pad, to receive the leaching solution therefrom. A plurality of emitters are connected in spaced relationship along each of the tubes for emitting the leaching solution at a controlled and substantially uniform rate over the pad and into the ore bed. At least some of the emitters are adjustable whereby different sets of flow passages can be utilized. The adjustable emitter comprises a sleeve slip-fit and rotatably mounted in a housing for rotative adjustment between at least two positions to alternately communicate the sets of flow passages with an inlet to the emitter.