ALLARD ENGINEERING SERVICES
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Relief Canyon ADR
Project:  FirstGold Corp. - Relief Canyon ADR:
Lovelock, Nevada


AES was retained to prepare complete detailed engineering designs for a 3,000 gpm activated carbon adsorption, pressure strip facility for the rehabilitation of the Relief Canyon Mine.  Part of the design criteria was to keep the facility within the existing process building.  Four pressure adsorption tanks were selected and a conventional pressure stripping system.  A unit carbon batch of 8 tonnes was selected.  The facility includes acid washing prior to stripping, carbon sizing; thermal reactivation and electrowinning.  The refinery and mercury containment were out of scope.

Unique features are the use of soft water for carbon rinse and R.O. water for strip makeup.  Pregnant and barren tanks were selected to minimize inventory and allow the existing ponds to be used for emergency containment.  The pressure adsorption train is plumbed so that any column can be the first in the series.  This feature reduces carbon transfer frequency and reduced flow during transfer.  Carbon is transferred from the adsorption columns by back pressuring the column.  The adsorption columns were designed with a hydraulically efficient baffle plate and AES designed bubble caps.

Purchase recommendations were made for all mechanical equipment and quotations were solicited for tanks and structural steel fabrication.

The project team that was assembled for execution of the design was as follows:

Geoff Allard, P.E. - Project Management, process design, piping and mechanical design.
Lehmann Designs & Concepts - Layouts, civil and structural design.
F. Jerome, P.E. - Electrical Design

The project generated 165 drawings and 145 engineering documents on a lump sum contract basis.  Drawings included flowsheets; mass balance; P&IDís; general arrangements; tank data sheets; demolition plans; structural drawings; foundation drawings; large bore spool drawings; small bore pipe isometrics with material takeoffs, pipe routing; pipe supports; electrical single lines; electrical schematics; MCC layout and conduit and cable schedule.  Engineering documents included calculations; piping specifications; purchase recommendations; tradeoffs; preliminary estimates; pump and pipe calculations; instrument data sheets; electrical and structural P.E. review; equipment list; transmittals and a host of other documents.

Pressure Adsorption Columns
Under Construction
Lower Adsorption Columns
Loaded Carbon Dewatering Screen
Upper Adsorption Columns
Soft Water & RO Tanks on Left; Strip Tank on Right
Strip column top, note clearance
Perspective View
Strip Column on Left; Holding Tank on Right