BASE METALS

Duluth sets Bechtel parameters for 100 year copper-nickel-pgm mine PFS

Duluth Metals' huge copper-nickel-pgm-gold resource on the Duluth complex in northern Minnesota moves on a stage with top engineering company Bechtel being given the parameters on which to base a PFS

Author: Lawrence Williams
Posted: Thursday , 22 Mar 2012

HONG KONG (Mineweb) - 

Talking to Duluth Metals Chairman and CEO, Chris Dundas at Mines & Money Hong Kong he remains extremely enthusiastic about his monster mining project in Northern Minnesota, USA which, if and when it comes to fruition, will become one of the world's great underground mining operations with a mine life probably well in excess of 100 years.  Top engineering company Bechtel has been retained to undertake the preparation of the NI 43-101 Prefeasibility Study (PFS) on the initial project based primarily on the Nokomis section of this vast resource and the parameters under which Bechtel has been instructed give a great indication of the scale of operations envisaged.

Bechtel has thus been instructed to prepare its study based on the following:

·         A vertically integrated mining complex;

·         Large scale phased underground mine plan and development;

·         Evaluating different scenarios respecting both on-site and off-site surface facility alternatives, including examining options in milling capacity up to approximately 80,000 tonnes/day throughput; and,

·         A hydrometallurgical plant with a minimum capability of producing copper cathode, nickel hydroxide and a platinum group metals concentrate.

An 80,000 tonne/day mining operation will make Nokomis one of the world's biggest underground mines on a scale with Codelco's El Teniente in Chile and LKAB's Kiruna iron ore mine in northern Sweden.

Back in North America, Vern Baker, President of Duluth Metals commented on this latest phase of the investigations, "Bechtel and the other Pre-Feasibility Consultants are aggressively working to define a large integrated mining operation that respects the environmental and social values of Minnesotans and which will benefit the State of Minnesota for generations.  This project is being planned with the latest technologies in order to protect Minnesota's environment and will be a long-term economic engine for Northern Minnesota."

The Bechtel PFS is only one of a series of engineering studies into this massive project, the potential scale of which should not be underestimated.  The geological structure which is the Duluth Complex is already reckoned to hold the world's third largest accumulation of nickel sulphides and the world's second largest accumulation of polymetallic copper and platinum group metals. . 

An initial pre-feasibility NI-43-101 Resource Estimate report on the consolidated resources of the Twin Metals Project is nearing completion by AMEC and is anticipated to be finalized by the end of April, 2012.  This report is going through final iterations as minor additions are incorporated into the geologic model.  This resource will be used for mine planning purposes in the pre-feasibility study.  This initial resource update will be followed up by a pre-feasibility resource report which will incorporate data from recent, current, and near future targeted drill programmes.

The Nokomis project comes under the Twin Metals 60:40 jv between Duluth and Antofagasta and together with Duluth's and the jv's other holdings in the Duluth Complex is believed to encompass one of the world's largest undeveloped repositories of copper, nickel and platinum group metals, with associated gold.  There are environmental concerns over the project lying as it does close to the Boundary Waters recreational area, but it also borders on the Minnesota taconite mining operations and indeed the options do include utilising brownfields areas for some of the operation's facilities.  The fact that it is envisaged to be an underground operation will also mitigate some of the environmental concerns. 

According to Dundas, the state and federal governments are supportive of the project, in particular because it brings great employment prospects to the area and also will be a great contributor to future U.S. domestic supplies of key metals and minerals.

To further emphasise the size of the resource controlled by the Twin Metals jv, the most recent resource statement comprises 550 million tonnes of Indicated Resources grading 0.639% copper, 0.200% nickel, 0.660 grams per tonne TPM (TPM = Pt + Pd + Au) for a copper equivalent (CuEq) grade of 1.51%, plus an additional 274 million tonnes of Inferred Resources grading 0.632% copper, 0.207% nickel, 0.685 grams per tonne TPM for a CuEq grade of 1.53%.  But this estimate was as of December 2009 and based on the Nokomis section alone and when a new resource estimate comes out from the AMEC study, scheduled for next month, it is likely to be considerably larger than this, particularly as the Twin Metals resource now includes a number of other major targets on the same structure acquired with the take-over of Franconia's neighbouring ground a year ago, and some extremely supportive drilling data obtained since the date of the last resource statement.

But Duluth also has wholly-owned exploration tenements adjacent to the Twin Metals resource for which Dundas has exceedingly high hopes that it will encompass the main feeders for the initial resource.  His geologists are very hopeful that this feeder will be particularly rich in nickel.  Permits to drill these areas are currently in process and Dundas hopes to have drill rigs turning on this during late summer.

As we've noted here before, this resource is likely to be so important to the Minnesota and U.S. economies that it's probably not a case of if it is developed, but when.  Any hurdles are likely to be overcome, but it still could be a couple of years or more before construction will actually start.  Dundas hopes it will be sooner rather than later - and is very confident this will be the case.