ZAMBIA is keen to negotiate larger holdings in new mining projects to raise its revenue and boost spending by investors on social projects, mines minister Paul Kabuswe said. The push by Lusaka through state-owned ZCCM-IH would apply to future agreements, but does not include existing mines and should not unnerve investors, Kabuswe told Reuters. Zambia is Africa's second-largest copper producer after the neighbouring Democratic Republic of Congo. ZCCM has interests of 10% to 20% in mines including those owned by Barrick Gold, Vedanta Resources and First Quantum Minerals. ZCCM sold a 51% stake in Mopani Copper Mines to a unit of…