Potash explorer Sirius Minerals' new finance director Andrew Lindsay has invested £99,000 in the company following his appointment. Lindsay was appointed on the same day that Sirius announced its acquisition of York Potash. He was previously finance director of AIM-quoted European Nickel.He has acquired 582,352 shares at an average share price of 17p. This gives him 0.07% of Sirius Minerals. The company issued 150m shares to acquire York Potash, which has mineral rights covering 600 square kilometres onshore and offshore in the Whitby and Scarborough areas. Sirius Minerals will also repay a £176,000 loan. The main asset of the business is the agreements with major landowners in relation to mineral rights.The mineral rights include potash and rock salt. There has been exploration in the past and large exploration targets have been identified. Management believes that there could be a significant potash resource in the form of polyhalite and potassium chloride. York Potash's founder Chris Fraser has become chief executive of Sirius Minerals. Top Director Buys Atlantic Coal (ATC) Director name: Mr Adam WilsonAmount purchased: 62,500,000 @ 0.65p Value: £406,250Sirius Minerals (SXX) Director name: Mr Andrew M LindsayAmount purchased: 582,352 @ 17.00p Value: £99,000VinaLand Ltd. (VNL) Director name: Mr Don Di LamAmount purchased: 100,000 @ $0.99 Value: $99,500VinaCapital Vietnam Opportunity Fund Ltd. (VOF) Director name: Mr Don Di LamAmount purchased: 50,000 @ $1.93 Value: $96,500@UK (ATUK) Director name: Mr David HollowayAmount purchased: 80,387 @ 12.44p Value: £10,000Top Director Sells Atlantic Coal (ATC) Director name: Mr Adam WilsonAmount sold: 85,000,000 @ 1.79p Value: £1,521,500KEFI Minerals (KEFI) Director name: Mr Ian Rutherford PlimerAmount sold: 800,000 @ 10.00p Value: £80,000KEFI Minerals (KEFI) Director name: Mr Ian Rutherford PlimerAmount sold: 800,000 @ 8.67p Value: £69,360KEFI Minerals (KEFI) Director name: Mr Ian Rutherford PlimerAmount sold: 750,000 @ 8.43p Value: £63,225Regency Mines (RGM) Director name: Mr Andrew BellAmount sold: 600,000 @ 6.41p Value: £38,460