Greg Harman

Thanks, Ellandra!  I was looking for bulk calcium carbonate of all kinds.
Lime, as it is processed, is a different ingredient for the recipe - serves as the cement component.
I think the Angliamix is using raw, crushed limestone chalk for the aggregate.
I'll keep searching -- you're right that I have to search out chalk mines and either get it from them or follow the trail from there.
I appreciate the response.

I'm wanting to try my hand at plastering over fixall (short-straw, fine cob) with chalk, lime, and hair (being used on restoration projects in the UK) and I would make the mixture myself, but I can't seem to find any supplier who sells big ole' bags of chalk (calcium carbonate) -- I mean like wholesale, 80-100 lbs.  There's plenty in art supply, food industry, and pharmaceutical suppliers with tiny little amounts of way-too-fine quality versions, hugely expensive.  Then, I suppose there's just trying to visit every school in eastern Washington State for their old supplies of chalk that no one is using anymore and crushing it myself (good re-use, pretty time intensive, and likely not much out there).  Any ideas?