* TSX up 9.16 points, or 0.06 percent, at 16,105.23
* Half of the TSX's 10 main groups move higher
TORONTO, Dec 11 (Reuters) - Canada's main stock index inched higher in morning trade on Monday, boosted by gains for materials stocks including fertilizer companies, while gold miners moved in both directions and railway stocks weighed.
* At 9:51 a.m. ET (1451 GMT), the Toronto Stock Exchange's S&P/TSX composite index .GSPTSE was up 9.16 points, or 0.06 percent, at 16,105.23.
* Half of the index's 10 main groups were in positive territory, with advancers outnumbering decliners by a 1.4-to-1 ratio.
* Potash Corp POT.TO was up 1.4 percent to C$24.68 and Agrium Inc AGU.TO added 1.3 percent to C$138.27 as the two fertilizer companies move closer to a merger.
* The materials group, which includes precious and base metals miners and fertilizer companies, added 0.6 percent.
* The heavyweight energy and financials groups were both flat, while industrials fell 0.2 percent as Canadian National Railway Co CNR.TO slipped 0.4 percent to C$102.71.
* Prometic Life Sciences Inc PLI.TO was up 7.1 percent at C$1.36 after a British health regulator gave one of its drugs a promising designation. Shopify Inc SHOP.TO added 2.4 percent to C$132.59 after the commerce software company was added to several S&P/TSX sub-indices.
* Several gold miners advanced even as the price of bullion steadied, with Iamgold Corp IMG.TO up 4.0 percent to C$6.76 and Yamana Gold Inc YRI.TO rising 2.2 percent to C$3.23. Kirkland Lake Gold Ltd KL.TO , meanwhile, was down 3.8 percent at C$17.24.