The following projects were selected to illustrate the range of assignments Argo is capable of successfully and effectively fulfilling:

Mineral Flotation

Flotation Reagent System Hazard Classification:

During engineering for a large Mexican mill expansion, the owner retained Argo Consulting to review the xanthate and dicresyl dithiophosphate mix-feed system hazard classifications assigned by the EPCM. Chemical hazard classifications determine the mechanical controls and electrical code standards to ensure personnel and plant safety. Setting standards that are too stringent makes the cost of meeting the classification excessively expensive and challenging. Xanthate molecules hydrolyze (break down) generating CS2 in the process that rapidly volatilize creating potentially explosive conditions. Argo determined an operating plan that allowed a non-hazardous classification, saving significant installation costs as well as preventing a retrofit of the older plant system. A breakdown product of dithiophosphate degradation product, although typically an insignificant possibility, is H2S which poses health problems at low atmospheric concentrations and an explosive hazard at higher concentrations. Unfortunately the dicresyl dithiophosphate product specified by the mine can be unstable, although posing a low probability of breakdown, Argo assessed that there was some risk and a normal H2S product classification was necessary.

Flotation circuit optimization:

A significant USA Pb-Zn-Ag mill had process improvement opportunities to capture and equipment obsolescence issues to contend. Bill Hancock developed a practical plan for froth washing to improve lead concentrate grades that offered significant shipping cost reductions. Results and metallurgical observations made during the froth sprinkling evaluations lead to followup QemScan mineralogical analyses that showed significant metallurgical opportunities could be obtained through flowsheet optimization. Subsequent plant flowsheet modifications were tested on the existing old circuit by actually redirecting flows to simulate different flowsheets and circuit residence times to assess metallurgical impact. Lab float tests were conducted in conjunction to assess optimum metallurgical targets. From that work the entire flotation circuits were replaced with higher conventional cell capacities on both the Pb and Zn circuits, additional flotation columns were installed on both the Pb and Zn circuits, Pb and Zn unit cells were installed and cleaner scavenger circuits were installed. Results: increased Pb recoveries ~ 5%, increased Zn recoveries over 10% with higher and more consistent concentrate grades, and Ag recoveries increased by 2%+.

Mill Expansion 3rd Party Engineering Review

A leading base metal, precious metal mining company who initiated studies for a significant mill expansion project retained Argo Consulting to provide independent monitoring and final review of the engineering metallurgical feasibility studies developed by their contractors. The review covered the entire breadth of studies including metallurgical baseline sampling and analyses, equipment sizing, plant layouts, costing, and installation time lines to allow full production rate during the expansion. Engineering and metallurgical reviews and assessments entailed ensuring plan consistency, accuracy and identification of any analytical gaps and missed opportunities to maximize the plan. Final work product was a report reviewing the project proposal that covered the project proposal that was submitted to the corporate Board of Directors for their review/approval.

Mill operator flotation training

Argo Consulting has provided several classroom courses to clients for flotation and process circuit operators which provides simple mineral processing fundamentals to help them understand the basics and provide them a perspective and understanding to improve their circuit control. Providing several operators this training at a time and away from the operation facilitates improved understanding and coordination between operators as well as provide a commonality for that coordination. This training was considered valuable by the several clients served. Further training info is provided on the Argo Operator Training webpage.

Potash flotation gypsum reduction and KCl recovery improvement

A USA potash mine utilizes flotation to separate very coarse KCl from NaCl from a mixed salt evaporate. Because of calcium contamination the potash product had sufficiently high levels of insoluble gypsum that posed a sedimentation problem when the KCl was dissolved by formulators. Hancock was hired to identify a gypsum flotation depressant and prove the effectiveness in plant testing. This was successfully accomplished and the assignment continued with technical and operations flotation training. The data collected from the depressant plant evaluations was further used the consultant for metallurgical modeling that lead to determining that the flotation capacity provided insufficient residence time to maximize KCL recoveries. Reducing the plant feedrate resulted in a significantly increased KCl annual production tonnage.

Water Treatment

Mine water ammonia and nitrate treatment process development

An Alaskan mine under development that was operating under a very strict operating permit encountered increasing ammonia (NH4-N) and nitrate (NO3-N) mine water discharge levels from the ammonium nitrate blasting agents used. Due to the limited land area available for installation of a biological plant sufficiently large to treat at least 1200 gallon/minute flowrates, Hancock was contracted to investigate and develop an innovative flowsheet that would provide a practical alternative to biological ammonia and nitrate degradation. The flowsheet developed that was bench tested with some cursory larger scale pilot tests included sequential and effective ammonia and nitrate ion exchange removal where the species were concentrated in strip solutions. These strip solutions were air stripped and a small bioreactor using brine tolerant bacteria. This was a innovative technically effective, relatively low capital cost and had good operating cost efficiencies alternative that met the project constraints provided by the client.

Mine water treatment plant startup and operator training

After an ~4 year shutdown, resumed mine activities required restart of the water treatment plant. The client hired Bill Hancock to support operational restart. Much of the previous operating experience had been lost during the intervening years. The assignment entailed working with the operators to check the mechanical soundness of the system, define initial operating conditions, trained the operators and conducted initial system optimization to ensure discharge permit limits were achieved.

Flocculation process control strategy for highly radioactive slurry

A DOE Hanford Site contractor responsible for transferring highly radioactive waste from leaking storage tanks to new bunkers that required a thickening and clarification step. The client required flocculation process expertise and hired Hancock to support their efforts. Due to the high radioactivity levels, the entire transfer process had to be accomplished in a 100% closed system that prevented observation. This required the client and consultant to develop highly effective thickening and clarification procedures that would be effective with all transfers to be made. The assignment entailed verifying flocculation process effectiveness, flowsheet review with improvement recommendations, providing training and developing a transfer procedure using simulant slurries as the actual materials were too radioactive to handle.

Water plant technical assessment

A mining company retained Bill Hancock to conduct a Colorado water treatment plant process technical assessment and plant capabilities audit in preparation for test mining and exploration work. The plant used a dissolved air flotation (DAF) process for clarification of predominant gypsum from the lime precipitation process followed by mixed bed filtration, thickening and belt filtration to consolidate the solids for haulage to waste disposal. Plant capability had to be assured because this mine was under intense environmental and local population scrutiny. An expert report was provided by the Consultant regarding the plant review along with recommendations for improving process performance.

Resolving drilling mud fluid negative impact on WTP clarification performance

Under new permit environmental limits, a USA mine installed a water treatment plant to treat a blend of mine water discharge and excess process mill water. The plant was misdesigned for the application and the client retained the Consultant to support resolution of the process shortcomings. Even after the flowsheet was optimized and the equipment upgraded, extended process excursions continued. In coordination with the client, further lab testing and assessments demonstrated that the diamond drilling synthetic drill mud combination was causing TSS hydrophobicity and particulate dispersion that was difficult to flocculate and clarify in the water treatment plant. The Consultant worked with drilling mud suppliers to assist in defining an improved mud formulation that would be easier to treat. Then a mud precipitation treatment program for drilling mud discharged to the mine water system was developed which the mine implemented. This combination greatly improved the water treatment process, which made it much more consistent and discharge limits manageable to consistently meet the discharge limits.


Coal Methane Control

A coal treatment company retained Argo Consulting to assess methane control treatment options for a western US underground longwall mining operation. The mine was experiencing excess methane levels as the coal was being cut which posed significant safety hazards. Argo visited the mine operations, reviewed the present dust control as related to potential methane chemical treatment method, conducted an intensive review of literature, and discussed the issue with several experienced coal researchers and operations personnel in the consultant's network. The client was presented with a technical option summary with the most viable and effective potential treatment options provided.

Process antiscalant product and marketing development

A chemical distributor had an important Russia Far East gold mill process antiscalant opportunity. Hancock was contacted to develop an effective chemistry formulation, established raw material sourcing, developed a technical treatment program and generated the necessary MSDS and product materials required. The distributor won the antiscalant business combined with a full range of other chemical commodity products which significantly streamlined their once a year logistics. And the antiscalant product provided excellent results in the mill process.

Sulfide collector technical marketing

A large international chemical producer has retained Argo to support their global sulfhydryl flotation collector business development. This is an ongoing technical marketing assignment that entails supporting sales agents technically and on a commercial basis, develop and generate effective marketing plans, develop products and product line recommendations to maximize commercial success, and to advise the client on the mining business in general.

Generating Mechanical Aerator Standard Performance Data

Acting in accordance with the definition of an independent engineer, Argo developed aeration rate and efficiency data for an aerator developed that an equipment company wanted to sell to the food processing and agricultural markets. Argo was responsible for the conduct of the 6,000 gallon pilot test in strict adherence to the ASCE/EWRI 2-06 standard protocol. KLa20 (oxygen transfer rate constant), SOTR (oxygen transfer rate, at standard conditions), SOTE (oxygen transfer uptake efficiency, at standard conditions) SAE (aeration power efficiency, at standard conditions), etc. aerator values were generated; the data developed was highly consistent that supported regressions having very low standard deviations.