GG vs NEM - statistical arbitrage strategy analysis

Continuing my previously mentioned strategy i will give u a great trade with the US STOCKS (GDX sector) GG and NEM. If my arbitrage stats analysis is right than for every 10 shares bought of GG stock u should sell 4 shares of NEM stock till the formula GG (daily close price) - NEM (daily close price)*0.4 = -0.9. At this point of time this formula equals to -1.88