hello preopen, page-13

can someone help me out.

i was reading the quarterly bauxite figures and didn't quite make sense of them. for example:
"The available alumina and the reactive silica in these 15 locations range from 52% to 21.6% and 0.9
to 6.6% respectively. The available alumina in the remaining 9 locations falls within 14.7% to
1.3% and the reactive silica ranged between 5.8 and 28%."

why is the alumina being reported as a high figure to low figure? and why is it interchangeably shown for the silica?
am i reading too much into it?

Cash increase due to oppies + Norsk Hydro