underclay technical
seat clay technical

I wish Ehrenberg would undertake a microscopical hunt for infusoria in the underclay and shales; it might reveal something.

Key words: soft mine floors, longwall mining, gate road stability, coal roads, soft underclay floors.

Depending on its physical characteristics, a number of different names, i.e. underclay, "fireclay", flint clay, and "ganister" can be applied to a specific seatearth.

The layer immediately underlying coal seams, often called either "seatearth" or "underclay", typically either consists of or contains a paleosol.

Unlike conventional brick-making clay, some fire clays (especially flint clays) are mined at depth, found as a seatearth, the underclay associated with coal measures.

In addition, shear strength of the moist underclay at the base of piles and changes in the floor dip are the controlling factors in the development of failures.

The alteration of sediments by weathering, plants, and other soil processes comprising underclay resulted in the formation of vast majority of fireclay that comprises underclay.

The stability is sensitive to changes in length of the lower part of the basal sliding surface, as well as to the configuration and shear strength of black and highly plastic underclay.

The bottom of the formation is placed either at the bottom of Buck Mountain (no. 5) coal bed or at the bottom of the underclay or shale bed below this coal measure.

In poorly developed paleosols, as seen in the soil profiles of modern poorly developed soils, called "Inceptisols", of modern river deltas and floodplains, there might not exist any noticeable alteration of the underclay.

It is also noted that sharp decreases in shear strength after peak values for the the underclay indicated that weak basal planes exhibit a shear strength at or approaching the residual value at the time of failure.

Depending on the specific underclay, these soil features can include some combination of pedogenic slickensides, pedogenic ped structures, illuviated clay pore fillings, different types of pedogenic microfabrics, rhizocretions, caliche nodules, root molds, and soil horizons.

These studies demonstrate that a paleosol, which is either developed in or comprises underclay, largely reflects the effects of plants and other soil forming processes on the underclay while it formed the ground surface prior to being buried by organic sediments.

Seated clay statue of Amitabha Buddha (No.45)

His father's mother, Teresita Chavez Romero, was a traditional ceramicist, known for her seated clay figurines and functional jars or ollas.