1. Realistic use of tailings
Dr. Rolf Arne Kleiv, Deptartment of Geology and Mineral Resources Engineering, Norwegian University of Science and Technology, Sem Sælands veg 1, NO-7491 Trondheim, Norway -
Rolf Arne Kleiv and Maria Thornhill
Realistic use of tailings
Geonor 2016, Mo i Rana, 16 March 2016 1

2. Quarry or underground mine
What are tailings?
In general, mineral production will yield two types of surplus materials (waste); waste rock from mining and tailings from mineral processing.
Feed
(Ore)
MINING
PROCESSING
Quarry or underground mine
Crushing & milling
Separation
Waste rock
(Surplus/waste)
Concentrate
(Valuable product)
Tailings
(Surplus/waste)

3. Why can’t the mining companies sell the tailings?
The volumes of tailings are often far in excess of market demands. Even large bulk applications become oversaturated.
The tailings are not pure mineral concentrates. Further processing (mineral separation) is often required to satisfy the specifications of potential customers.
The process that produced the tailings may pose restrictions on both direct use or further processing (size distribution, use of process chemicals).
Unless the tailings contain rare minerals or have extraordinary qualities, the competition is huge. (’All’ tailings contain quartz and feldspar).
Many potential applications can be classified as low price commodities. Hence, location and logistics becomes critical. Handling and transport cost represent a major limitation.

4. How much tailings do we produce?
Lifetime consumption of mineral commodities (USA 2015)
Copper
450 kg
Tailings kg
Lead
400 kg
Zinc
250 kg
Gold
50 g
Rock, gravel and sand kg
Iron ore kg
Cement kg
Clay
5200 kg
Other minerals kg
Phosphate minerals
7600 kg
Other metals
800 kg
Bauxite
2400 kg
Salts kg
Source: The Society for Mining, Metallurgy and Exploration Foundation

5. Cu Pb 29 82 Is recycling the solution?
Fraction of consumption that is being covered by recycling 29 Cu 82 Pb
Kilde: UNEP, Global Metals Flow Working Group

6. How much copper do we need?
18 000
World population (millions)
16 000
Annual copper production (1000 tonnes)
14 000
Annual per capita consumption (g/person)
12 000
USA and Western Europe annually use ca. 10 kg pr capita, whereas India uses ca. 0,5 kg per capita.
10 000
8 000
6 000
4 000
2 000
1900
1920
1940
1960
1980
2000

7. Use of tailings – positive and negative effects
Potential positive effects
Economic profit
Reduced need for new mining
Reduced need for transportation
Reduced deposition costs
Reduced need for new deposits
Tailings improvement
Reduced environmental impact from depositing
Potential negative effects
Increased processing costs
Increased consumption of energy and chemicals
Remaining (reprocessed) tailings could be less environment friendly.
Loss of quality in products
Increased need for transportation
The net effect is not always positive.
We should aim for optimal use of the mineral resources (including tailings).
Demanding 100% utilisation for new deposits is counterproductive and not the optimal environmental solution. Cost/benefit-analyses should be performed.

8. Further work…
At NTNU, we would like to address the following questions:
What have we learned so far from working towards increased utilisation of mineral resources, nationally and internationally?
How, and to what extent, do governments encourage increased use of tailings?
How, and to what extent, do governments place restrictions on deposition or use of tailings?
What has been done with respect to cost/benefit-analysis on use of tailings?
How should we evaluate the use of tailings against tailings improvement or tailings deposition?

9. Thank you for your attention
Photo: NTNU Info