Environmental Stewardship

Materials

Materials are separated into two categories: raw materials (the ore from which we extract product) and associated process materials (materials that are used in processing but are not part of the final product).

Raw Materials

We extract ore from both open pit and underground operations. This ore is either processed through a mill or placed on a heap leach pad to extract the product.23 In 2015, we processed 70.7 million tonnes (Mt) of ore, compared with 75.8 Mt in 2014.

Raw Materials Processed24

Associated Process Materials

To process the ore and extract metals, we use materials such as lime and cyanide. The table below shows our main processing materials.

Associated Process Materials and Recycled Input Materials25

2015 2014 2013
Cyanide (t) 30,800 23,100 26,500
Lime (t) 83,500 86,200 180,600
Sodium metabisulphite (t) 3,300 4,000 3,900
Grinding balls (t) 36,400 28,500 39,800
Other reagents (t) 57,400 56,800 61,800
Total (t) 211,400 198,600 309,100

Recycled Input Materials

Recycled input materials used at our mines include mainly waste oil, used grinding balls, fly ash, biosolids and used liners. All of these recycled materials are sourced internally.

Recycled input materials as a percentage of our total tracked input materials (excluding raw materials and fuel) was 4% in 2015.

2015 2014 2013
Recycled fly ash (t) 7,500 10,300 11,200
Used oil (t) 150 500 1,000
Used liner (t) 0 100 100
Biosolids (t) 200 7,200 95,100
Other recycled materials (t) 1,200 2,200 4,900
Subtotal, recycled (t) 9,050 20,300 112,300
Total, all materials used (t) 220,500 218,900 424,900
Percent from recycled 4% 9% 26%