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Reclamation of Phosphatic Clay Waste Ponds by Capping. Volume 1: Centrifugal Model Evaluation of Reclamation Schemes for Phosphatic Waste Clay Ponds

02-030-056Final

Abstract

This part of research was conducted to evaluate reclamation schemes for minimizing the turnaround time between mining and reclamation by enhancing consolidation of these waste clays.

Traditionally, 1-9 bench tests using graduated cylinders have been used to evaluate clay settling rates and consolidation. Unfortunately, this method is unsatisfactory as (a) the stress levels are lower than field conditions, and (b) excessive testing times are required. Offsetting these limitations is the use of centrifugal modelling techniques by which prototype stress levels are applied and testing times reduced due to shortened drainage paths.

The results of these centrifugal model tests demonstrated that centrifugation is a viable method for examining prototype waste clay disposal schemes, provided modelling of models is used for determining the time scaling exponent, and sand segregation potential in s/c mixes is considered.

The descending order of disposal technique effectiveness in achieving the highest final solids content is: (a) sand capping (staged), (b) s/c mix capping, (c) s/c mix 1:1 to 2:1, (d) flocculants or untreated clay. The time required, however, is in proportion to the solids content; e.g., higher solids content require longer times.
Reclamation of Phosphatic Clay Waste Ponds by Capping.

Other Volumes

FIPR Publication No. 02-030-061
Volume 2: Centrifugal Modeling of the Consolidation Behavior of Phosphatic Clay Mixed with Lime or Gypsum. University of Florida. April, 1988.

FIPR Publication No. 02-030-062
Volume 3: Evaluation of the Use of Geotextiles for Capping Phosphatic Waste Clay Ponds. University of Florida. April, 1988.

FIPR Publication No. 02-030-063
Volume 4: Piecewise Linear Computer Modeling of Large Strain Consolidation. University of Florida. April, 1988.

FIPR Publication No. 02-030-075
Volume 5: Centrifugal Model Evaluation of the Consolidation Behavior of Phosphatic Clays and Sand/Clay Mixes. University of Florida. March, 1989.

FIPR Publication No. 02-030-073
Volume 6: Consolidation Properties of Phosphatic Clays from Automated Slurry Consolidometer and Centrifugal Model Tests. University of Florida. February, 1989.