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    Red River to restart Hillgrove gold production this year

    Red River Resources Limited (ASX: RVR) has announced an encouraging update on its Hillgrove gold-antimony project in NSW.

    Red River reported that it would use Hillgrove’s plant and infrastructure to restart gold production in 2020 and leverage high gold prices.

    The company said that the results from Bakers Creek Waste Dump demonstrate it is a fast restart opportunity.

    RVR reported that the metallurgical testwork on Bakers Creek samples generated positive results. The company said that the gravity concentrate testwork undertaken indicated 60-65% gold recovery, while the flotation concentrate testwork indicated that a further 20-25% of gold can be recovered.

    RVR said that the onsite gravity and flotation concentrate leaching is likely to produce gold doré with total gold recovery of gold contained in the Bakers Creek feed material of 75-80%.

    The Bakers Creek Waste Dump has an Exploration Target of 200,000 – 300,000 tonnes at 2.0 – 3.0 g/t Au.

    Hillgrove project

    The Hillgrove Project is located approximately 30km from Armidale in New South Wales.

    The project has a current a material high-grade Mineral Resource at Hillgrove including Mineral Resource of 2.8Mt @ 5.1 g/t Au & 1.7% Sb reported in accordance with the 2012 JORC Code; and Mineral Resource of 3.9Mt @ 4.7 g/t Au & 1.3% Sb reported in accordance with the 2004 JORC Code, with potential to convert to Mineral Resources reported in accordance with the 2012 JORC Code.

    The Mineral Resource is contained within 6 key hubs in the Hillgrove Mineral Field. They are Metz Centre; Bakers Creek; Brackins Spur; Eleanora/Garibaldi; Freehold; and Clarks Gully.

    Bakers Creek

    The Baker’s Creek is the largest gold production centre in field and the deepest workings in Hillgrove Field. The gold production at the mine had ceased because of the limited technology at the time for mining at ~500m depths and the mineralisation remains open.

    The Bakers Creek waste dump was created during the mining of the Bakers Creek Mine, between 1877 to 1921. The dump is approximately 105m by 70m in area and 15-20m deep. Ore was hand sorted underground and again on surface, with the dump containing material rejected during surface hand sorting.

    Restarting gold production at Hillgrove

    The company had commenced the work to restart gold production at its Hillgrove Gold Project.

    The company reported that the review of 137 samples from six Bakers Creek Waste Dump sampling programs since 1982 returns weighted average grade of 2.5 g/t Au.

    Red River reported that it plans to restart gold production at Hillgrove in 2020 using infrastructure to take advantage of current high gold price. RVR said that the work has commenced on a conceptual flowsheet, and the progress will be updated as it happens.

    Positive results from metallurgical testwork

    The company said that the metallurgical testwork was carried out by Consep (gravity concentrate) and Core Resources (flotation concentrate and cyanide leach tests) on representative samples derived from a 423kg bulk sample taken from the Bakers Creek Waste Dump in 2019 by Red River.

    RVR said that the metallurgical testwork carried out by Consep and Core Resources has demonstrated the viability of treating Bakers Creek Waste Dump material through the existing Hillgrove Mill with total gold recovery to saleable gold doré produced onsite estimated to be 75-80%.

    Consep gravity concentrate testwork

    The company reported that Consep tested Bakers Creek Waste Dump samples using its extended gravity recoverable gold (GRG) test procedure and found samples to contain a high GRG content of 81.1%. The GRG is predominately classed as Coarse.

    RVR said that the modelling of a suitable gravity circuit by Consep indicates that 60-65% of the gold in the Bakers Creek Waste Dump would be recovered by gravity methods to a gravity gold concentrate. It is estimated that in excess of 95% of the contained gold in the gravity gold concentrate will be recovered by cyanide leaching to gold doré on site.

    Core Resources flotation concentrate and cyanide leach tests

    The company said that Core Resources’ flotation testwork on the Bakers Creek Waste Dump samples generated a gold recovery of 83.9% to a flotation gold concentrate. This concentrate then underwent gold cyanide leaching tests which indicated a gold recovery of 85%.

    Conceptual flowsheet

    Red River said that the highly positive metallurgical testwork outcomes from the Bakers Creek Waste Dump enabled it to focus on a conceptual flowsheet to maximise the gold recovery using existing plant and infrastructure on site.

    RVR reported that using existing infrastructure, it will load and truck material from Bakers Creek Waste Dump 4.2km to the Hillgrove Mill, where it will be crushed and ground.

    The company said that a new gravity gold concentrator will be installed in the grinding circuit to produce a gravity gold concentrate. It is estimated that approximately 60-65% of gold contained in the feed material will report to the gravity concentrate.

    RVR said that the remaining material will then be treated through the existing flotation circuit to produce a flotation concentrate. Red River estimates that a further 20-25% of gold contained in the feed material will report to the flotation concentrate.

    Total gold recovery to the combined gravity and flotation concentrates is estimated to be about 80-90%.

    RVR said that the gravity gold concentrate and flotation gold concentrate will then be leached on site using cyanide to produce saleable gold doré. The total gold recovery to a saleable gold doré is estimated to be 75-80% of the contained gold in the Bakers Creek Waste Dump feed material.

    The company said that the current gravity circuit in the Hillgrove Mill would require upgrading (XD20 model Knelson Concentrator or similar) to process Bakers Creek material and Red River would add a cyanide destruction circuit to the mill.

    Red River said that it is also investigating the potential of an intensive cyanide leach circuit to maximise the gold recovery from the gravity gold concentrate.

    Management comments

    Red River Managing Director Mel Palancian said, “These results from Hillgrove show we can re-start gold production from existing onsite material. Having only acquired Hillgrove in August 2019, we are pleased that results to date have validated our strategy to expand our operations and we are progressing our plans to restart Hillgrove production before the end of 2020.”

    Jonathan Norris
    Jonathan is a founder of Mining.com.au and has been covering the resources industry since 2018. With over 17 years experience in print, broadcast and online media, Jonathan has seen first hand the transformative effect of online niche media.

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    • Delayed Prices (USD) - Last Updated 01-07-2022
    • Gold $1,819.00
    • Silver $20.75
    • Platinum $916.00
    • Palladium $1,898.00
    • Dalian Iron Ore i2209 $121.63
    • Aluminium $2,491.00
    • Cobalt $72,460.00
    • Copper $8,365.50
    • Lead $1,971.00
    • Nickel $23,158.00
    • Tin $26,800.00
    • Zinc $3,333.00