my earnings forecasts, page-15

Now think about what you just said.

Why on earth would anyone imagine that Jinchuans smeltering costs are going to increase just because the price of nickel has gone up?

Read this.... AGM are NOT paying Jinchuan to smelter their nickel. They are selling Nickel Concentrate to Jinchuan.

So Jinchuan offer the maximum price they can afford to get the nickel.