Eliminating Water Dependency in Gold Mining and Processing

Request Number REQ2353227
Due Date November 14, 2017
Author Seh-Rin Sung
Request for Proposal Details
RFP Title
Eliminating Water Dependency in Gold Mining and Processing
RFP Description

NineSigma, on behalf of Hochschild Mining and any of its subsidiaries and affiliates (collectively “Hochschild”), invites solution providers to develop proposals for a cost-effective method for extracting gold from the Volcan Mining Project (“Volcan”), eliminating, or at least significantly reducing, water dependency for both mining and processing.


Hochschild’s Volcan Mining Project located in northern Chile is a new play with 389.7 million tonnes of Measured and Indicated resources grading 0.709 g/tonne of gold, containing 8.88 million ounces of gold.  The site, located high in the Andes mountains has limited water available.  Because of its remote location, water conveyance to the site is very problematic and economically unattractive.  As the traditional method of extracting gold from bulk ore by heap leaching requires substantial quantities of water with significant water losses occurring through evaporation, Hochschild seeks an alternative process.


Hochschild is interested in developing processes to extract gold ore that are cost-effective and eliminate, or at least minimize, the dependency on water.


Since none of the ore has been mined yet, this project is a “clean slate” opportunity to propose novel methods for gold extraction.


See Table 1 for typical characteristics of the Volcan ore.  Composition of the ore in the play varies by location, but this table defines characteristic ranges for composition.  The ore has about 0.7 g of gold per tonne, with gold particles ranging from 5 to 15 µm.  About 75% of the gold present is trapped within a quartz matrix.


Table 1.  Mineralogical Composition of Volcan Ores. Columns represent samples from different locations.




The pre-feasibility study of the project states:


 “Gold-copper mineralization at Volcan is related to the intensely developed hydrothermal alteration that gave rise to the native sulphur deposits. The hydrothermal system was a consequence of the sub-volcanic intrusion of dacitic to microdioritic porphyry into a complex of domes and lava flows of dacitic composition.


[Mineral] occurrences are associated with [...] subvolcanic intrusive events [that] are responsible for the extensive and widespread [...] high sulphidation epithermal style alteration and mineralization.”


Compaction tests show a general amenability to percolation even when loaded.


Bond Work Index grindability tests resulted in a ball mill work index of 17.4 kWh/tonne (relatively high) at 100 mesh.  Pre-feasibility tests indicate that tertiary crushing would be required to liberate the gold.


Anticipated Project Phases or Project Plan


Phase 0 – Proposed method review

  • Propose or describe a method of gold extraction that meets the technical objectives of this RFP, providing supporting evidence or reason to believe the process may be feasible. Describe your assessment for potential success and any potential limitations.  Hochschild will evaluate submissions and select all promising approaches for proof of concept engagement, to be negotiated as warranted.


Phase 1 – Proof of concept

  • Demonstrate proposed process at lab scale. As needed, 10 kg ore samples from the Volcan mine will be made available to those offering a potentially promising path forward to test their process on the target ore body composition.  Based on lab scale results, promising methods will be supported for scale up investigations.  Site visit as warranted.
Phase 2 – Engineering co-development, under appropriate agreements negotiated between the parties.  With the assistance of Hochschild technical staff,
  • Assess economic feasibility of approach
  • Optimize process parameters
  • Develop a scalable pilot process for 2-3 tons/day


All proposals submitted in response to this Request for Proposal do not constitute an offer.  Any proposals selected to move to each of the project phases will not be deemed as a Hochschild acceptance of such proposal nor an agreement (nor a commitment to enter into an agreement) with any solution provider.  Hochschild’s only commitments under this RFP will exclusively derive from the execution of a definitive agreement between Hochschild and the solution provider.


Key Success Criteria

Suitable methods / technologies should:

  • Eliminate the use of water
    • At least, the process should minimize the need for water and be efficient in water recovery and reuse
    • Preferably, the process does not require water
    • Submissions that demand the least amount of process water will be looked at more favorably
  • Recover at least 70% of the gold present in the ore
  • Offer an economical process to concentrate gold from mined ore over traditional heap leaching in a remote and arid environment


Possible Approaches

As none of the ore has been mined yet, this project presents a “clean slate” opportunity to propose novel methods for gold extraction where an entire process can be developed with minimal constraints other than the elimination or at least significant reduction of water usage for mining and ore processing.  


Hochschild Mining is open to:

  • Technologies that have been developed for other ore targets which may be adaptable here
  • Technologies that may already exist for gold but could not have been implemented elsewhere
  • Approaches or technologies being developed in academic or other research labs
  • Great ideas with a rationale that can be substantiated through accepted scientific principles


Possible approaches might include, but are not limited to:

  • Mechanical methods
  • Physical methods
  • Chemical methods
  • Biochemical methods
  • Any combinations thereof


Approaches not of interest

  • Proposals which only offer non-recuperable water treatment as a solution


Preferred Collaboration types
Items to be submitted

Your response should address the following:

  • Non-confidential description of proposed technology and working principle
  • Availability of technical data including gold yield and operating parameters
  • If you have published, presented or patented your technology, please provide reference/s.  If using a third party proprietary license or open source technology, please provide description.
  • Technical maturity of the approach (concept, reduced to practice, prototype, ready to implement, active on industrial scale)
  • Pathway to industrial scale including timing, estimated budget, and capacity for manufacture
  • Estimated cost to process 1 ton of ore
  • General position on intellectual property (existing or co-developed with funded support)
  • Desired relationship with sponsor
  • Team description and related experience


Appropriate responses to this Request

Responses from companies (small to large), consultants, entrepreneurs, or inventors are welcome.  For example:

You represent a company or university that has demonstrated a proof of concept.

You represent a company or university that has reduced method to practice at lab scale.

You represent a company or university that has developed a method for use at pilot scale.

You represent a company or university that has demonstrated a method ready for implementation at industrial scale.

You represent a company or university that has developed a method for processing another ore that could be adapted to process client’s ore.

You represent a technology transfer agency that represents an inventor or technology holder who can demonstrate an approach to address the request.

You represent a university research department that has a bench-scale demonstration ready to adapt.

You represent a university research department that has an undeveloped pathway with a high probability of success.


Area of Interest
Request Priority
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