A pump system (10) for a pipeline (100) is disclosed that incorporates a pump (12) connectable to a supply pipe (101) and a discharge pipe (102) of the pipeline (100). The system (10) further includes a flow impeding device (22) which in one form is part of a valve (14) operative to selectively establish a plurality of restricted flow passages (30) at a first portion (105) of the discharge pipe (102). The restrictive flow passages (30) increase the resistance to flow of the medium at the first portion of the discharge pipe so as to restrict the flow rate of the medium being discharged by the pump (12) to below a threshold level. A valve (14) and valve member (22) is also disclosed. The system (10) has particular application for mining operations and methods of controlling a pump operation and retrofitting a pump system are also disclosed.