At a conference in the capital of sao tome and principe monday chevron s public and government relations representative jonathan lifa said that the operations were estimated to cost between us 400 000 and us 700 000 per day but it had not been determined how long they would last 周一在圣普首都的一次会议上,雪佛龙的公共和政府关系代表乔纳森说,预计开采工作将每天花费40万到70万美元。但是还没有决定开采期限有多长。