The Chief Financial Officer (CFO) of newly-merged Glencore Xstrata has spent over a million pounds-worth in shares, taking advantage of the stock's recent slump.1807 Clarendon Limited, a company in which CFO Steven Kalmin has an interest in, snapped up 400,000 shares in the firm at a price of 276.4p a pop, spending just of £1.1m.Kalmin joined Glencore back in 1999 as the general manager of finance and treasury functions at its coal industrial unit, before becoming CFO in 2005.The move came after a 24% fall in the share price over the last three months as mining stocks bore the brunt of falling commodity prices and ongoing market volatility. The multibillion-pound tie-up between commodities trader Glencore and mining group Xstrata came into effect in May. In its maiden trading update as a combined company, the firm revealed last month that production across most asset classes was higher in the first quarter than the year before, though its marketing division did see "some softening in prices" towards the end of the period.Top Director BuysEW Group Ltd (EWG) Director name: Mr John MortonAmount purchased: 7,477,277 @ 1.18p Value: £88,232F&C Asset Management (FCAM) Director name: Mr Edward BramsonAmount purchased: 23,000 @ 90.91p Value: £20,909ISG (ISG) Director name: Mr Jonathan HoultonAmount purchased: 12,900 @ 155.00p Value: £19,995Produce Investment (PIL) Director name: Mr Derek PorterAmount purchased: 10,000 @ 150.00p Value: £15,000Top Director SellsPorvair (PRV) Director name: Mr Ben StocksAmount sold: 175,000 @ 283.07p Value: £495,372Porvair (PRV) Director name: Mr Christopher TylerAmount sold: 46,000 @ 283.07p Value: £130,212