(ShareCast News) - Shares in Mineral sands producer Sierra Rutile fell nearly 17% on Tuesday morning as it was announced that its proposed $375m merger with Australian zinc miner Iluka Resources is to be delayed by a German regulator calling for a longer review of the deal.Reportedly the German antitrust authority needed more time to consider the merger due to the complexity of the mineral sands market, and initiated phase two proceedings which will take up to three months to conclude.AIM-listed Sierra Rutile and Iluka have five business days to agree on how to proceed as either company may terminate the merger if they do not come to an agreement.Sierra Rutile planned to cancel its shares on AIM on 9 September due to the merger, but because of the phase two review, the cancellation will be rearranged at a later date."So why are the German Antitrust Authority getting involved? Is it because Germany hosts a number of traders and consumers of titanium mineral sands? Might they be flexing muscles afforded by the European Union? The chances are that the Authority will allow the deal through though it is possible that there may be some conditions applied to Illuka's dominance in the market for zircon supply," analysts at SP Angel said. "It is our view that the revenues and profits of mineral sands consumers have been long and unjustly held back by a relatively small group of specialist consumers, though we note that no anti-competition review has been launched into the actions of consumers in this respect by any German Authority."Shares in Sierra Rutile were down 16.55% to 29p at 1133 BST.