Lime was used for agricultural purposes and for making cement.
For 60 years until 1993, the company was the only one licensed to make cement in the country.
"It isn't just that they're brilliant at making cement."
Gravel and substrates used for making cement are mined in the area.
It can be used to glaze ceramics and make cement.
These have been used in the past for making cement.
They could make cement, and developed large irrigation networks.
"It's like making cement: if you make it wrong, it'll collapse."
The material is also in widespread use in making cement.
Someone asked Mary how she learned to make cement.