Mexican Economy Minister Sergio Garcia de Alba said Wednesday that talks with the US aimed at settling a 15-year-old dispute over cement import duties are "very advanced," and that an agreement could be announced in coming weeks.   Speaking at a press conference, Garcia de Alba declined to go into any detail about the talks, which have generated optimism that Mexican cement makers could soon boost their exports to the US to help confront shortages there.  Shares of Cemex reportedly rose 4.7 per cent and those of Grupo Cementos Chihuahua closed up 1.5 per cent.  
 
 On Thursday, the US Department of Commerce plans to announce the results of a review on duties that Cemex has to pay for exports to the US. A preliminary review in August suggested a reduction in tariffs to 40.54 per cent from 54.97 per cent.