Safety first in mining

Renaissance of heap leaching for valuable metals

(OneStone)

1 Prinzipbild zur Haufenlaufung # Schematic diagram of the heap leach process

(OneStone)

(Alacer Gold)

2 Dichtungsbahnen und Drainage bei der Haufenlaugung # Sealing pads and drainage in heap leaching

(Alacer Gold)

(Gold Fields)

3 Tarkwa Mine in Ghana # Tarkwa mine in Ghana

(Gold Fields)

(Timmings Gold Corp)

4 San Francisco Haufenlaugungsprojekt in Mexiko # San Francisco heap leach project in Mexico

(Timmings Gold Corp)

(Comanco Environmental Corp)

5 Fort Knox Haufenlaugungsprojekt in Alaska # Fort Knox heap leach project in Alaska

(Comanco Environmental Corp)

(FLSmidth)

6 Mobiler Stacking/Reclaim Förderer, Typ Racetrack # Mobile stacking/reclaim conveyor, type Racetrack

(FLSmidth)

(Outotec)

7 Reactor (Tank)-Leaching Verfahren # Reactor (Tank) leaching process

(Outotec)

(GFMS, OneStone)

8 Entwicklung der Goldgewinnung # Development of world gold production figures

(GFMS, OneStone)

(LME)

9 Preisentwicklung von Kupfer und Nickel # Price development of copper and nickel

(LME)

(LME, OneStone)

10 Relative Preisentwicklung von Kupfer und Nickel # Relative price development of copper and nickel

(LME, OneStone)

(CST Mining Group)

11 Haufenlaugung von Kupfer # Heap leaching of copper

(CST Mining Group)

(Outotec)

12 SX/EW-Verfahren # SX/EW process

(Outotec)

(Talvivaara Mining Company)

13 Oxidatives Bio Heap-Leach Verfahren # Oxidative bio-heap leach process

(Talvivaara Mining Company)

(Alacer Gold)

14 Konventionelle Haufwerksbildung # Conventional heap stacking

(Alacer Gold)

(CST Mining Group)

15 Haufwerkserzeugung mittels Radialbandförderer # Heap stacking by radial belt conveyor

(CST Mining Group)

(Terra Nova Technologies/AMEC)

16 Teleskopierbares Haldenband # Telescopable heap stacking belt

(Terra Nova Technologies/AMEC)

17 Link-Förderbänder # Link conveyor belts

(Terra Nova Technologies/AMEC)

(FLSmidth)

18 Mobiler Stacking-Förderer # Mobile stacking conveyor

(FLSmidth)

(AngloGold Ashanti)

19 Sprengung bei Cripple Creek & Victor # Blasting at Cripple Creek & Victor

(AngloGold Ashanti)

20 Cerro Vanguardia Goldmine in Argentinien # Cerro Vanguardia gold mine in Argentina

(AngloGold Ashanti)

(Terra Nova Technologies / AMEC)

Kupfer Haufenlaugungsprojekt in Chile # Copper heap leach project in Chile

(Terra Nova Technologies / AMEC)

(Alacer Gold)

21 Çöpler Haufenlaugungsprojekt in der Türkei # Çöpler heap-leach project in Turkey

(Alacer Gold)

(CST Mining Group)

22 Erzbrecher in Lady Annie Kupfermine in Australien # Ore crusher in Lady Annie copper mine in Australia

(CST Mining Group)

(Talvivaara Mining Company)

23 Talvivaara Bio-Minenbetrieb in Finnland # Talvivaara bio-mining operation in Finland

(Talvivaara Mining Company)

24 Mobiler Stacking-Förderer # Mobile stacking conveyor

(Talvivaara Mining Company)

Summary

A very broad range of processes are used for the recovery of valuable metals. Heap leaching as a hydrometallurgical process is one of the cheapest methods and particularly useful in the case of ores with a low metal content. These characteristics are especially attractive to so-called junior mine operators who have relatively little available capital. However, the subject of leaching is a controversial one, because its use for the recovery of gold and silver requires the use of highly-toxic sodium cyanide as the leaching agent and therefore involves a number of hazards. On the other hand, the biological heap leach processes that have become established for nickel and copper recovery have proved to be environmentally-sound methods. This report provides details of market trends, technologies and safety standards and discusses the economic background of selected projects.

1 Introduction

Heap leaching is the term used for hydrometallurgical extraction processes in which crushed and ground ore is heaped up and then sprayed with an aqueous chemical solution in order to dissolve the valuable metals out of the rock [1]. Since the 1970s, heap leaching has become accepted as a practical and cost-effective process for recovering valuable metals like gold, silver and copper from ores with a low metal content. More recently, the process was also used for recovering nickel, zinc and other metals. Relatively low capital cost and operating expenses compared to conventional...