Petropavlovsk is only group set to join bluechip FTSE 100 index

GOLD producer Petropavlovsk, formerly Peter Hambro Mining, is expected to be the only company promoted to the FTSE 100 index when the latest quarterly indexes review is announced tomorrow.<br /><br />Tour operator Thomas Cook Group looks set to be demoted back to the mid caps after a poor run by its shares with the sector hit by the credit crisis which has prompted many people to stay at home rather than take expensive vacations.<br /><br />Petropavlovsk&rsquo;s promotion, if confirmed, will take the number of mining companies in London&rsquo;s benchmark index up to 12, increasing their hefty weighting in the blue chip index.<br /><br />The third-largest gold producer in Russia, Petropavlovsk only entered the London Stock Exchange main market in April this year after buying back Aricom, the iron ore producer it had originally spun out in 2003.<br /><br />Thomas Cook shares, meanwhile, have fallen nearly 15 per cent over the past three months, markedly underperforming a 6.7 per cent rise by the FTSE 100 index.