Overview
Stage | Production |
Mine Type | Underground |
Commodities |
|
Mining Method |
|
Processing |
- Smelting
- Agitated tank (VAT) leaching
- Counter current decantation (CCD)
- Carbon in pulp (CIP)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
|
Mine Life | 7 years (as of Jan 1, 2018) |
The Company’s expectations and Aura expects Gold Road to declare commercial production in the 4th quarter of 2020. |
Latest News | Aura announces first gold shipment from the Gold Road mine September 17, 2020 |
Company | Interest | Ownership |
Aura Minerals Inc.
|
100 %
|
Indirect
|
Gold Road Mining Corp.
|
100 %
|
Direct
|
Deposit Type
- Epithermal
- Vein / narrow vein
Summary:
The mineralization at the Gold Road Mine consists of quartz-calcite-adularia veins within the northwesttrending Gold Road fault zone. The fault zone can be over 150 ft (46 m) wide and quartz vein(s) may occupy one or more strands within the structure. Vein strands usually occupy the footwall, hanging wall or a central portion of the structure, but strands may occur in two or all three of these positions within the same area. Where the fault zone is narrow (such as areas within the Gold Road latite) vein material may occupy the entire structure.
The “main” Gold Road vein occupies a strong fault fissure, typical of the district. This structure was formed by several separate movements before, during and after gold mineralization. The strike of the sinuous vein varies from N50°W to N66°W and generally dips 65° to 85° to the northeast, though locally the vein can be vertical or dip steeply to the southwest. The vein system crops out continuously for about 7,500 ft (2,286 m) on the Property, including a segment that is in ore grade mineralization on the surface for over a mile (1,524 m). Most of the ore has been mined in wide lenses within dilatant zones of the vein structure. The wider dilatant zones of the vein may be related to areas of north- to northeast-curving concavity along the sinuous normal fault.
The character of the Gold Road vein varies considerably along its vertical extent. In the lowest stratigraphic exposures, the vein consists of fine-grained chalcedonic and banded quartz in a braided or complex stockwork vein system up to 30 ft (9 m) wide hosted in Oatman latite. At stratigraphically higher exposures where the vein is hosted in Gold Road latite, the vein is a tabular, fissure-like body typically 3-7 ft (0.9-2.1 m) wide. Historically, high-grade ore has only been mined from the Gold Road vein within Oatman latite and Gold Road latite. At the highest exposed levels, the Gold Road vein cuts lithologies of the Upper Volcanics series (Sitgreaves Tuff and Antelope quartz latite). This upper zone generally coincides with the Red Top prospect area. Mineralization at Red Top consists of very fine grained chalcedonic quartz and siliceous sinter deposits reflective of the uppermost levels of a low-sulfidation epithermal system, near the paleosurface or paleo-water table. Quartz mineralization at Red Top is several inches to a foot (0.3 m) wide and does not contain significant gold mineralization. Although the character of Gold Road vein varies depending on host rock, the changes in the vein at formation contacts are not sharp and abrupt. There is a gradual narrowing of the vein system upward.
The mineralogy of the Gold Road vein is typical of the district. The deposit is interpreted to be a lowsulfidation, epithermal vein deposit. The vein consists mostly of quartz with local concentrations of calcite and adularia. At least five major stages of quartz deposition are present in the vein. The last two stages of quartz, which consist of pale green to deep honey yellow, fine- grained chalcedonic silica and breccia, appear to have accompanied most of the ore grade gold in the vein.
Gold is the most valuable constituent of the ore at the Gold Road Mine. Silver occurs with the gold in a ratio of approximately one part gold to one part silver on average. Sulfides are rare in the ore, but do occur in higher grade shoots. Fluorite is locally present. High-grade ore frequently contains very fine-grained free gold, copper sulfides or carbonates and, rarely, cerargyrite (AgCl) in thin quartz bands. Most gold is microscopic.
Summary:
The historic operations, which utilized shrinkage stope mining, were reviewed with added consideration to operating areas that could be potentially improved. The excellent ground conditions and steeply dipping ore offered the availability of alternative mining methods that were suggested. Historically long hole stoping and a modified Alimak raise mining method were used with less than favorable results, higher than expected dilution, higher operating costs and less productivity. The RPM review and discussion for the Shrinkage Stoping Mining (SSM) and the Raise Access Mining (RAM) methods mining method is as follows.
RPM is of the opinion that RAM should be the preferred underground mining method for the following reasons;
- Limited to no exposure of the miners to unsupported ground due to the protection offered by the raise climber
- Limited ground control costs – only required during the raise mining phase
- Reduced development costs since the raise is developed in ore.
The typical RAM stope will be a total of 60 ft. along strike, 200 ft high along dip and have an average mining width of 5.5 ft. This typical ore block represents 4,900 tons of material with a nominal gold grade of 0.19 opt using the calculated dilution factor of 14%.
A review of continuing to use conventional shrink stope mining was completed by RPM. The method is well known and has been used historically for many years including at the Gold Road mine. The following design criteria was used to estimate the productivity and estimated costs to be used for mine design planning as well as comparison to other mining methods.
The assumption is that the development, in waste, required to access the stope area is in place and will not be part of these costs. These development costs as well as all other costs would need to be determined and included in a full mine plan and cash flow model.
Raise Access Mining (RAM)
Raise Access Mining is a relatively new method used to mine vertical narrow vein areas in a safe and efficient manner. The typical RAM stope will be a total of 60 ft. along strike, 200 ft. high along dip and have an average vein width of 5.5 ft. This typical ore block represents 4,900 tons of material with a nominal gold grade of 0.19 opt using the calculated dilution factor of 14%. RAM, also known as Alimak Mining has been developed over the past decade as a safe, cost effective and proven technology to allow production mining in narrow veins with a limited amount of dilution. The advantages of the mining method are:
- Less development with greater advance along the dip of the ore thereby minimizing the number of sill levels and associated lateral development cost.
- Limited, to no exposure to unsupported ground for the miners.
- Faster access to ore production.
- Better ground control and lower costs since the only area that requires ground control is directly within the Alimak raise area.
- Lower unit costs than other methods.
- Capital costs for Alimak machines have dropped to an estimated US$500,000 per machine.
- One of the disadvantages is that experienced Alimak miners demand a premium wage although with more machines in use the number of experienced miners is increasing.
The Gold Road operations current use the 11,000 ft. one-way decline to access the mine. All men and materials use the 12 ft. by 12 ft. decline. The restart of the mine will use two 20 tonne haul trucks (plus one spare) supplied by the contractor. The trucks will continue to be used throughout the LOM although will only haul to the new shaft loadout pocket when it is ready in Year 2. The development of a shaft to be used for ore and waste only has been reviewed and developed by Gold Road. The plan is to use a raise bore to construct a new 8 ft. diameter shaft with the capability to move ore and waste – there will not be any men or material moved in the shaft.
Gold Road has negotiated and reviewed a budgetary contract to lease a headframe that would be installed over the new shaft. The headframe is 70 ft. high has a 685 hp motor and all of the required control circuits. The drum diameter is 96 in by 59.5 in wide. The rope size is 7/8 in and has a 3.5 ton capacity skip. The new shaft will be 900 ft. deep plus sufficient room to include a loadout pocket and sump at the bottom. The overall installed cost for the raise, hoist and equipment is US$1.9 M. The shaft haulage is expected to have an operating cost that is less than 50% of the historic truck haulage costs.
The new shaft is developed by using a contractor to drill a pilot hole and then back ream the new 8 ft. diameter shaft. Cuttings developed from the raise bore will be on the 900 level and will be trucked to the surface to be placed on the waste dump. The raise bore process is expected to take 2-3 months. After successful completion of the raise bore project the new shaft is fitted with the new guides and support. A working deck is used to complete the ground control and shaft infrastructure requirements including installing the rope guides. The shaft project is expected to take 10 months and cost an estimated US$1.9 M. Ongoing lease payments for the headframe will be made by Gold Road for the LOM.
Processing
- Smelting
- Agitated tank (VAT) leaching
- Counter current decantation (CCD)
- Carbon in pulp (CIP)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
Flow Sheet:
Summary:
The Gold Road ore-processing facility consists of a conventional 500-ton/day-capacity carbon-in- pulp (CIP) mill that was built in 1995. The mill has, from the time it was constructed up to the present time, processed about 1.1 million tons of ore, operating about one third of the time. It was last in operation in 2016. The mill incorporates two-stage crushing, two-stage grinding, 24- hour leaching, CIP adsorption, carbon-stripping, electrowinning, and refining. Tailings are pressure filtered and conveyed to a dry-stack tailings storage facility (TSF). The grind of the plant is 80% passing 325-mesh (45 µm) and the gold recovery is about 95%.
Ore from the mine is either directly dumped in the primary-crusher dump hopper or reclaimed from the adjacent stockpile by a front-end loader and placed in the dump hopper. A vibrating feeder feeds the ore to a jaw crusher and the crushed product, in combination with the product of an adjoining cone crusher, is conveyed to a vibrating sc ........

Commodity | Parameter |
Gold
|
Recovery Rate, %
|
Gold
|
Head Grade, oz/ton
|
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Production:
Commodity | Units | Avg. Annual (Projected) |
Gold
|
oz
| 203,569 |
All production numbers are expressed as payable metal.
Reserves at May 3, 2018:
Category | Tonnage | Commodity | Grade | Contained Metal |
Inferred
|
978,000 tons
|
Gold
|
0.22 oz/ton
|
214,000 oz
|
Corporate Filings & Presentations:
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News:
News | Date |
Aura announces first gold shipment from the Gold Road mine
|
September 17, 2020
|
Aura Completes Acquisition of Gold Road Project from Para
|
March 30, 2020
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Aura Enters into Definitive Agreements for Purchase of Gold Road Project from Para
|
March 9, 2020
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Aura Agrees to Purchase Gold Road Mine and Related Transactions with Para
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February 10, 2020
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Para Resources Announces First Dore Pour at the Gold Road Mine
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November 7, 2019
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Para Resources Announces Start of the Gold Road Mill
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October 24, 2019
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Para Resources Inc.: Phase 1 Drilling Program on Tr-Ue Vein in Oatman, Az. Vein width of between 0.61 m and 4.7 m at grades between 9.4 and 13.6 gpt Au
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September 17, 2019
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Para Resources Announces the Start Up of the Gold Road Mill
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February 28, 2019
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Para Starts Mining at Gold Road Mine in Oatman, Arizona
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February 5, 2019
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Para Resources Signs Agreement for Contract Mining at Gold Road Mine
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November 15, 2018
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Para Resources Signs Agreement for Contract Mining at Gold Road Mine
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November 15, 2018
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Para Resources Announces Positive Preliminary Economic Assessment for the Gold Road Mine
|
May 1, 2018
|
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