The Red Dog VIP Mill Optimization Project
The Red Dog Mine is both the largest known zinc reserve and the largest zinc producer in the world. The mine started in 1989 and by 1999 had increased production from ~300,000 tonnes per year of zinc concentrate to in excess of 900,000 tonnes per year. The VIP Mill Optimization project further increased the zinc concentrate production to 1.1 million tonnes per year while improving both the product quality and the zinc recovery. The VIP Mill Optimization project also addressed a number of issues related to risk reduction: power generation capacity, water treatment capacity and concentrate thickening.
As the title implies, this project was about optimization. During previous expansions, the crushing and grinding capacities had been expanded leaving the flotation circuits as the production limiting step. With the flotation circuits as the production limiting step, it had been policy to maintain minimum product quality and sacrifice zinc recovery in order to maximize the mill throughput. It was thus decided to expand the flotation circuits to match the maximum crushing and grinding capacity while improving both concentrate quality and zinc recovery.
The project was faced with numerous challenges, the most daunting of which was the schedule. This $105 million project was to be executed, from conception to completion, inside of 2 years. The testwork through delivery of materials and equipment portion of this schedule had a duration of less than 9 months. The project was also faced with a restricted ice-free shipping window of 100 days, the challenges of construction in an Arctic environment and an extremely tight labour market for qualified craft personnel. The project successfully addressed these challenges with several innovative approaches to project execution including an Alliance contracting arrangement between the Owner, Engineer and Contractor, modular construction in Anchorage and a “fast-track” approach to engineering, procurement and construction.
This paper focuses on the innovative project execution techniques implemented to meet these challenges, bring the project in on budget and achieve the design intent.
Zinc, MILL OPTIMIZATION