Identification of Available Equipment Types and Vendors

Identification of Available Equipment Types and

Vendors

A wide variety of equipment is marketed for size and density separations

within the mining industry. However, the equipment is typically designed for

coarser and higher density materials. Although there is a significant body of

knowledge pertaining to the principles of operation of individual pieces of

equipment, there is little guidance in developing a treatment train for processing

soils and sediments. Fines, often termed slimes, are considered an operational

problem in the mining industry, and are removed as a waste stream prior to

making the principal separations. Contaminated sediment separations, however,

involve making efficient separations near or within that "waste" fraction, and

require the ability to handle and even recover the finest residuals. The condition

of the materials presented to the plant will be highly variable, depending upon

whether they are consolidated materials excavated from a CDF, or mechanically

or hydraulically dredged sediments processed at the time of disposal. In situ

water content may vary from 50 to 150 percent, presenting difficulty in handling

and in processing through equipment designed for dry (less than 10 percent

moisture content), or noncohesive, material. Previous testing of laboratory-scale

mining equipment has demonstrated that the feed limitations are not always well

defined, and the normal operating parameters may not interface well with the

separations of interest for soils and sediments. Even among Architect/Engineer

firms with experience in soil washing, assemblage of a treatment train appears to

be something of an art, with the configuration varying depending upon specific

site conditions. The result is an unacceptable number of operational unknowns

for the layman and highly localized expertise within the consulting industry,

which ultimately translates to prohibitive cost.

The significant objective of this phase of the project then was to evaluate

how the equipment industry has responded to the potential in the sediment

remediation arena: identifying the critical core pieces of equipment necessary for

the key separations of interest and the minimum necessary auxiliary equipment

required in support. The desired outcome is a portable testing unit that (a) is

economical to purchase and operate, (b) can be supported with widely available

equipment, (c) is adaptable to operational conditions and constraints at different

facilities, and (d) is technically simple, operable by field personnel with a

reasonable amount of preliminary instruction and technical support.

Testing of Candidate Equipment

The core unit to be evaluated under this project was a hydrocyclone

separator. Performance factors for the equipment considered for demonstration

and purchase were as follows:

a. The experience of the offeror in conducting size separation studies with

dredged material and/or soil.

b. Suitability of the equipment to separate sediment/soil at the 75-m target

size cutoff.

Chapter 1 Introduction