Gruyere project - Mineral Resources
The Mineral Resources and Mineral Reserves for the Gruyere deposit were updated by Gold Fields at 31 December 2017. The Resource and Reserve for the ancillary Attila and Alaric deposits have been updated by Gold Road with technical review by GFA. Gold price inputs were consistent across both companies at A$1,850/oz and A$1,600/oz for the Mineral Resource and Mineral Reserve respectively. Mineral Resources and Mineral Reserves are reported in accordance with the requirements of the SAMREC and JORC Codes.
Since assuming operational and management control of the Gruyere JV in January 2017, Gold Fields and the JV management team has initiated further review and technical studies aimed at consolidating and optimising the delivery of the project on time. Project de-risking, contractual agreements and evaluation of additional production and productivity opportunities are ongoing.
Mineral Resource classification
The GFI 50% share, as held by Gruyere Mining Co Pty Ltd, is reported below.
| Tonnes (kt) | Grade (g/t) | Gold (koz) | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Classification | Dec 2017 | Dec 2016 | Dec 2015 | Dec 2017 | Dec 2016 | Dec 2015 | Dec 2017 | Dec 2016 | Dec 2015 | |||||||||||
| Open pit | ||||||||||||||||||||
| Measured | 7,175 | 7,281 | – | 1.18 | 1.29 | – | 272 | 302 | – | |||||||||||
| Indicated | 48,856 | 47,685 | – | 1.29 | 1.33 | – | 2,030 | 2,046 | – | |||||||||||
| Inferred | 19,413 | 21,855 | – | 1.33 | 1.36 | – | 831 | 959 | – | |||||||||||
| Total open pit | 75,444 | 76,822 | – | 1.29 | 1.34 | – | 3,134 | 3,307 | – | |||||||||||
Mineral Resources classification per mining area
The total project, as well as the GFI 50% share, as held by Gruyere Mining Co Pty Ltd, is reported below.
| Measured | Indicated | Inferred | Total Mineral Resource | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mineral Resources areas | Tonnes (kt) | Grade (g/t) | Gold (koz) | Tonnes (kt) | Grade (g/t) | Gold (koz) | Tonnes (kt) | Grade (g/t) | Gold (koz) | Tonnes (kt) | Grade (g/t) | Gold (koz) | |||||||||||||||
| Open pits | |||||||||||||||||||||||||||
| Gruyere | 14,060 | 1.2 | 526 | 91,518 | 1.3 | 3,732 | 37,883 | 1.3 | 1,620 | 143,461 | 1.27 | 5,878 | |||||||||||||||
| Attila | 289 | 2.0 | 19 | 4,995 | 1.6 | 261 | 294 | 1.7 | 16 | 5,578 | 1.65 | 296 | |||||||||||||||
| Alaric | – | – | – | 1,199 | 1.7 | 67 | 650 | 1.3 | 26 | 1,849 | 1.56 | 93 | |||||||||||||||
| Total open pits | 14,349 | 1.18 | 545 | 97,712 | 1.29 | 4,060 | 38,827 | 1.33 | 1,662 | 150,888 | 1.29 | 6,267 | |||||||||||||||
| GFI share | 7,175 | 1.18 | 273 | 48,856 | 1.29 | 2,030 | 19,414 | 1.33 | 831 | 75,444 | 1.29 | 3,134 | |||||||||||||||
Notes:
All Mineral Resources are completed in accordance with the SAMREC Code and JORC Code 2012 (Attila and Alaric pits)
All figures are rounded to reflect appropriate levels of confidence. Apparent differences may occur due to rounding
Mineral Resources are inclusive of Mineral Reserves
Figures are reported on a 50% attributable basis unless otherwise specified
All Mineral Resources reported at various cut-off grades according to material type and distance to the Gruyere Mill (in construction). Gruyere – 0.34g/t Au (fresh), 0.30g/t Au (transitional), 0.29g/t Au (oxide) Attila
All mineral resources are constrained within an $1850/oz optimised pit shell derived from mining, processing and geotechnical parameters that could be realistically applied to these deposits during future economic extraction. In the case of the Gruyere resource, no allowance for an open pit ramp has been included in the geotechnical parameters used to generate the constraining whittle shell
Modifying factors
- All Mineral Reserves are quoted in terms of RoM grades and tonnages, as delivered to the metallurgical processing facilities, and are therefore fully diluted
- The Mineral Reserve Statements include only Measured and Indicated Mineral Resources, modified to produce Mineral Reserves that are contained in the LoM plan
- Mineral Resources and Mineral Reserves undergo regular internal and/or external audits, and any issues identified are rectified at the earliest opportunity – usually during current reporting cycle
- The Measured and Indicated Mineral Resources are inclusive of Mineral Reserves
| December | ||||||
|---|---|---|---|---|---|---|
| Units | 2017 | 2016 | ||||
| Mineral Resource parameters | ||||||
| Mineral Resource gold price | US$/oz | 1,400 | 1,275 | |||
| A$/oz | 1,850 | 1,.700 | ||||
| Cut-off for open pit | g/t | 0.34 | 0.5 | |||
| Mineral Reserve parameters | ||||||
| Mineral Reserve gold price | US$/oz | 1,200 | 1,125 | |||
| A$/oz | 1,600 | 1,500 | ||||
| Cut-off for mill feed open pit | g/t | 0.42 | 0.43 | |||
| Strip ratio (waste:ore) | ratio | 2.80 | 2.77 | |||
| MCF | % | 100 | 100 | |||
| Dilution open pit | % | 4.9 | 3.2 | |||
| Plant recovery factor | % | 91 | 91 | |||
| Processing capacity | Mtpa | 7.5 | 7.5 | |||
Mineral Reserve classification
The GFI 50% share, as held by Gruyere Mining Co Pty Ltd, is reported below.
| Tonnes (kt) | Grade (g/t) | Gold (koz) | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Classification | Dec 2017 | Dec 2016 | Dec 2015 | Dec 2017 | Dec 2016 | Dec 2015 | Dec 2017 | Dec 2016 | Dec 2015 | |||||||||||
| Open pit | ||||||||||||||||||||
| Proved | 7,616 | 7,435 | – | 1.11 | 1.09 | – | 271 | 260 | – | |||||||||||
| Probable | 41,060 | 38,350 | – | 1.21 | 1.21 | – | 1,600 | 1,500 | – | |||||||||||
| Total open pit | 48,676 | 45,785 | – | 1.20 | 1.20 | – | 1,871 | 1,760 | – | |||||||||||
Mineral Reserves classification per mining area
The total project, as well as the GFI 50% share, as held by Gruyere Mining Co Pty Ltd, is reported below.
| Proved | Probable | Total Mineral Reserve | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mineral Reserves areas | Tonnes (kt) | Grade (g/t) | Gold (koz) | Tonnes (kt) | Grade (g/t) | Gold (koz) | Tonnes (kt) | Grade (g/t) | Gold (koz) | |||||||||||
| Open pits | ||||||||||||||||||||
| Gruyere | 14,908 | 1.09 | 524 | 78,853 | 1.20 | 3,039 | 93,761 | 1.18 | 3,563 | |||||||||||
| Attila | 323 | 1.68 | 17 | 2,889 | 1.54 | 143 | 3,212 | 1.55 | 160 | |||||||||||
| Alaric | – | – | – | 379 | 1.49 | 18 | 379 | 1.49 | 18 | |||||||||||
| Total open pits | 15,231 | 1.11 | 542 | 82,120 | 1.21 | 3,200 | 97,352 | 1.20 | 3,741 | |||||||||||
| GFI share | 7,616 | 1.11 | 271 | 41,060 | 1.21 | 1,600 | 48,676 | 1.20 | 1,871 | |||||||||||
Notes:
The Mineral Reserve is completed in accordance with the SAMREC Code
Gold Road holds an uncapped 1.5% net smelter return royalty on Gold Fields Ltd's share of production from the Gruyere project JV once total gold production exceeds 2Moz
The Mineral Reserve for the Gruyere deposit is evaluated using a gold price of A$1,600/oz and is evaluated using variable cut-off grades: Oxide 0.35g/t gold, Transitional 0.39g/t gold and Fresh 0.42g/t gold; Attila – 0.70 g/t Au (fresh), 0.60 g/t Au (transition), 0.55 g/t Au (oxide); Alaric – 0.67 g/t Au (fresh), 0.62 g/t Au (transition), 0.57 g/t Au (oxide)
Ore block tonnage dilution averages and gold loss estimates: Gruyere – 4.9% and 0.4%. Attila – 14% and 3%. Alaric – 20% and 6%
All figures are rounded to reflect appropriate levels of confidence. Apparent differences may occur due to rounding
| Grade tonnage curve - Surface | |
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