NARTEY-TOKOLI AND OTHERS v. VOLTA ALUMINIUM CO. LTD. (NO. 2) Labour—Collective agreement—Capacity to negotiate—I.C.U. and Valco only parties to collective agreement—Valco subsequently negotiating "Leave of absence without pay/recall programme" (L.O.A.) with local union and W.D.C.—Whether L.O.A. in relation to collective agreement valid under provisions of Act 299—Industrial Relations Act, 1965 (Act 299), ss. 5, 6-7 and 10.