GMC Chart, page-69

Not US$1600/tonne

Today's spot price for FeSi75, which is modelled to be used in GMC's smelting process[1], is between USD $940 ~ $960 / tonne[2].

Even better if GMC has contracted FeSi75 in the past 12 months, because FeSi75 prices got smashed and reached a low of USD $800 ~ $830 / tonne in the past 12 months [3] and the contract price will be even lower than that.

Say, we use a more pessimistic number of USD $900 / tonne, then that will be USD $900 * 0.43 = $387 worth of FeSi75 used per tonne of ferromanganese alloy smelted.

Whereas realistically, it is probably closer to around $350 worth of FeSi75 used per tonne of ferromanganese alloy smelted.

The modelled price for ferromanganese alloy sales is USD $1850 per tonne less 5.5% selling fee [1].​

DYOR, IMO​

[1] http://gulfmanganese.com/wp-content/uploads/2018/07/SC-GMC-060718.pdf
[2] http://www.ccmn.cn/tiehejin/tiehejinprice/2018-08-17/ff8080816427fd36016545fde103127a.html
[3] http://www.ccmn.cn/tiehejin/tiehejinprice/2018-04-19/ff80808162c439c70162dbf94369385a.html