The Non-Executive Chairman of Russia-focused resources group Highland Gold Mining invested over one million pounds in the firm one day after the stock reached a 52-week low.As has been the case with the wider mining sector, the share price has suffered since the start of the year as commodity prices took a hit; Highland has dropped by over a third, falling to the year's low of 52.5p by Wednesday's close.Chairman Eugene Shvidler, who was appointed in 2008, chose this as a good time to buy, snapping up 2,174,351 shares at that price on Thursday for a total of £1.14m. The purchase raised his stake in the company to over 37m shares, equal to an 11.45% interest.Chief Executive Valery Oif also bought 310,622 shares at the same price for £163,077, pushing his stake 4.46%.The transactions came on the same day the AIM-listed company announced that the processing plant at its Belaya Gora project in Russia had successfully tested material without interruption, paving the way to commercial production.Highland expects to produce between 30,000-50,000 ounces of gold from the project this year, ramping up to 75,000-110,000 ounces per annum over the life of the mine. Top Director BuysHighland Gold Mining Ltd. (HGM) Director name: Mr Eugene ShvidlerAmount purchased: 2,174,351 @ 52.50p Value: £1,141,534Finsbury Growth & Income Trust (FGT) Director name: Mr Anthony TownsendAmount purchased: 51,500 @ 479.75p Value: £247,071Highland Gold Mining Ltd. (HGM) Director name: Mr Valery OifAmount purchased: 310,622 @ 52.50p Value: £163,077Cranswick (CWK) Director name: Mr Bernard HoggarthAmount purchased: 9,000 @ 1,165.27p Value: £104,874Cambria Automobiles (CAMB) Director name: Mr Philip Swatman Amount purchased: 165,000 @ 30.50p Value: £50,325Avanti Communications Group (AVN) Director name: Mr David J WilliamsAmount purchased: 15,000 @ 166.25p Value: £24,938Mission Marketing Group (TMMG) Director name: Mr Peter FitzwilliamAmount purchased: 85,000 @ 23.40p Value: £19,890Berkeley Group Holdings (The) (BKG) Director name: Ms Veronica WadleyAmount purchased: 800 @ 2,203.00p Value: £17,624Booker Group (BOK) Director name: Mr Helena Andreas Amount purchased: 10,000 @ 127.66p Value: £12,766Frontier Mining Ltd (DI) (FML) Director name: Mr Yerlan Zhenisovitch AliyevAmount purchased: 860,000 @ 1.45p Value: £12,470BC