Plainsman Ravenscrag Quarry in 2025:

It is Getting Complicated

This has served the company for almost 50 years. The grinding plant, which has also served 50 years, has been able to process these clays to 20 and 42 mesh. While this quarry has been a key advantage for the company and coarsely ground bodies still sell well, the demand for smoother, more plastic and whiter bodies has seen a steady trend to the use of more and more imported 200 mesh powders (eg. clays, feldspar, silica) to make bodies. The star clay in the quarry is 3B, it is smooth and contains natural feldspar. Minings are typically done now just to get it. But because it is near the bottom (there are 6 layers plus overburden), others continue to bloat the inventory of unneeded materials (some of these piles are 30+ years old). On the next mining, the cost of stockpiling the overlying layers vs discarding them will have to be rationalized.

Most of these piles (especially the ball clay) could be sold on the open market if 200 mesh grinding was possible. The most serious problem is the amount of overburden that must be removed. Perhaps even more serious, since other clays are not needed, the 3B has to bear the entire cost of the mining. Now that better, more accessible and easier to mine clays further east have been found, the way forward is looking much better. In fact, it looks so promising (with testing of course) that it could be time to begin reclaiming this site.

This quarry has one saving grace: The bottom layer, which has been left in the ground the last two minings, 3D. It is the clean (low in contaminants) and, like 3B, contains natural feldspar. But it is not plastic, its usefulness depends on a better quality ball clay.

Related Pictures

Three gifts have just fallen into our lap

Reflecting on where we have been and need to go

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Mother Nature has been good to us, giving a quarry in Ravenscrag, Saskatchewan, that has served us 50 years. It has always felt good to tell customers, "these rustic, textured, natural bodies are what Mother Nature gives us". We have made a science of helping customers take such bodies beyond their limits. However, change has happened. Expectations have increased. Many more users are hobbyists, they prefer not to deal with documentation yet want more plastic and smoother bodies with margin for error against failure. They use hundreds of bright colored commercial glazes that look better on bodies that are vitreous and whiter burning. Since we cannot make these from the materials in our current quarry and with our grinding equipment, the trend has thus been our relentless move toward making bodies made from imported materials.

However, gifts from three sources have just fallen into our lap that could reverse this:
-Mother Nature: Higher quality fireclays, kaolins and ball clays are available further east in the province.
-The current economic and trade climate: Higher-quality products made from low-cost domestic clays, less dependence on US imports.
-We don't have to open a new mine; existing mines in the "El Dorado" zone are available.
Couple these with mounting mining costs and a glut of unused stockpiles at our current quarry, it seems time to accept the gifts and move forward in exciting new ways.

Mel Noble at Plainsman Clay's Ravenscrag, Saskatchewan quarry

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Six different sedimentary clays are extracted from this quarry. It was opened in the 1970s, the best location available at the time. These test bars were made by slaking select lumps from each layer (thus exhibiting their best performance). The left-most dried test bars show the layers (top to bottom). The A1 top layer is the most plastic and has the most iron contamination (it is used in our most speckled reduction firing bodies). A2, the second one down, is a ball clay (similar to commercial products, although darker burning), it is very refractory and the base for Plainsman Fireclay. A3, third from top, is a complete buff high-temperature stoneware (like H550), although sandy and over-mature at cone 10. 3B, third from bottom, is a smooth medium-temperature stoneware; it contains significant natural feldspar (although fired color and particulate contamination are the most variable). The second from the bottom, 3C. fires the whitest and is the most refractory (it is the base for H441G). The bottom one, 3D, the best product in the quarry. Although the least plastic and most silty, it is also very fine particled and the cleanest (consistently free of particulate impurities and sand), it pairs very well with a ball clay to make a cone 6 stoneware.

Here is why new grinding equipment is a really good idea

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These two pieces have been fired to cone 6, without glaze, I use this as a way of comparing changes in the character of the fired surface over time. These are made from a mix of A3 and 3B, our two main raw stoneware clays. The mix has been ground to 42 mesh (using our hammer mill). These materials vary in the amount of sand they contain and the amount of iron stone concretion particulates, so we will also see smoother and more speckle-free than this as a matter of normal variation. We have made sandy and speckled clays like this for so long that they seem normal to me. Yes, rustic bodies do have their appeal. However, the limits of our particle size reduction equipment and current quarry materials have resulted in importing American materials to satisfy customers who want smoother, whiter, more plastic and more vitreous bodies. We are now producing tens of thousands of boxes a year made from these imported materials! Transporting expensive clays at great distances begs the question of why we have not better leveraged the clay resources that are right here. That, and associated independence, quality and lower production costs, are coming soon.

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