Mixing Shore Pac^® Mixing Directly In Excavation

The Shore Pac polymer may be mixed either directly within the excavation or pre-mixed in surface vessels. The mix water or the prepared fluid shall be treated with appropriate additives as specified by the manufacturer.

Mixing Directly In Excavation

When mixing directly in the excavation it is important to have a steady stream of water or recycled fluid that is positioned to provide a point of rapid and wide water flow for introduction of polymer by sprinkling or sifting. Mixing of fresh polymer shall be completed by sprinkling or sifting the polymer carefully onto a flowing stream of water or fluid from a pressurized source directed into the excavation, such that the flowing fluid catches, wets and separates the polymer grains so that they disperse and hydrate as individual particles, avoiding the forming of lumps or balls of un-mixed polymer. Dry polymer shall not be added directly onto the fluid in the excavation (as opposed to being added on a flowing stream) because this normally produces lumps or “fisheyes.”

When a new polymer mix is being prepared in a hole that has been dug to significant depth before adding slurry, the excavation shall be filled with water to a water column height (measured from bottom of excavation) of not less than one meter or 15% of excavation depth, whichever is the greater, before beginning to add the polymer. Shore Pac® dry granular polymer shall be added at a controlled rate on the stream of water that is filling the hole in order to avoid lumps and fisheyes. The excavating tool (auger, bucket, clamshell) shall be reciprocated gently the full length of the slurry column while the polymer is being added, to distribute and even out the fresh polymer, and to assure that none of the polymer settles to the bottom of the excavation during the mixing and thickening process.

When adding fresh dry polymer to recycled fluid directly in the exaction, special care must be taken to assure good dispersion of the polymer grains to avoid forming lumps. This is because the polymer wets-out and disperses more slowly in thickened fluid than in plain water. Fanning the recycled fluid across an auger or other object to provide a point of wide and rapid flow facilitates the adding of fresh dry polymer.

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