AXP regarding the hydrocyclone equipment contemplated by LAC for use at Thacker Pass:

" John Evans said in an interview that they will employ a hydrocyclone to separate lithium rich particles from lithium poor. This technology is very straightfoward and works based on the size and density of the particles. I don't believe this setp was included in their PFS and this should reduce the upstream capital expenditures required for the plant, or potentially allow a higher rate of production (if this is a rate limiting step)."

Microsoft Word - 207071-00100-00-GE-REP-0005_RA_NI 43-101-2018-08-01 FINAL (lithiumamericas.com)

This link is the PFS from 1 August 2018 on Thacker Pass by LAC.  Pages 135-141 covers the proposed processing as of the release of the PFS.  Additional references include, in the same document, pages 76-84 and on pages 5-8.

 Drawing your attention to page 76 of that document, under part 13 ( titled:  " Mineral Processing and Metallurgical Testing" ):  "In 2017, LAC decided to pursue an alternative approach that would reduce overall operational and capital costs, and leverage the physical properties of the soft claystone. To this end, a new process flow sheet that uses conventional leaching and industry-proven purification technology has been developed. Technical indicators obtained from tests so far are encouraging and support continued optimization, pilot testing, and engineering."

And for emphasis, look again at that last sentence in the paragraph above:  "Technical indicators obtained from tests so far are encouraging and support continued optimization, pilot testing, and engineering."

That continued optimization, pilot testing and engineering is, if I am not mistaken, the purpose of the Reno "Process Research Facility".  So, what has been learned since 1 August 2018 when the PFS was released?

Page 6 of the  document includes this statement:  "The current flowsheet does not include an allowance for traditional ore upgrading, and further investigation of ore upgrading is recommended at the next engineering phase, although it is not necessary to the viability of the project."  So the PFS doen't allow for upgrading, but "further investigation of ore upgrading is recommended at the next enginnering phase".  Is the Reno Lab the "next engineering phase" and prior to the DFS?  Just asking.

Back to the reference to "hydrocylone" that AXP mentioned in his post today, Yup, there was no reference to the use of the hydrocyclone in the PFS of 2018.  AXP notes a reference to a statement of Jon Evans.  I don't know when Evans made that statement, but an updated Thacker Pass note from LAC, dated 25 September 2019, does in fact make reference to the hydrocyclone technology.  I don't know whether that addition came from LAC directly or from the partner they revealed that year as being the company that would be operating the mine at Thacker Pass:  Sawtooth Mining Company, LLC.

The following paragraph from the 25 September LAC NR Update on Thacker Pass does, infact, give reference to the hydrocyclone:

"Process Engineering & Design Process Testing Facility The Thacker Pass process optimizes and reconfigures several commercially-proven techniques in extractive metallurgy designed specifically for the processing of lithium bearing clays. To date, Lithium Nevada’s process testing facility located in Reno, Nevada has produced over 3,000 kg of high-quality lithium sulfate brine (“lithium sulfate”) from Thacker Pass ore. The process has been optimized by upgrading the ore through a wet attrition process followed by a hydrocyclone to remove coarse material with relatively low lithium content. The process test work has demonstrated an increase in lithium concentration by over 25% which results in reduced acid consumption per tonne of LCE."

Highlights added by me and not in the original paragraph.

So, what, exactly, is a hydrocyclone and what does it do?

I have poste some time way back about the use of the hydrocyclone on this Hub, but it is worth repeating:

The hydrocylone as used in mining dates all the way back to the late 1800's and is anything but new technology.  It is used to separate the big stuff from the smaller stuff, just using plain English to simplify the whole thing.

The hydrocyclone establishes internal to its architecture a cetrifugal vortex that is used to separate the discharge from the hydrocyclone into two parts:  an overflow and an underflow.  Ideally this separation will separate fine particles from coarse particles when pressure, volume and internal diameters at key points of the hydrocyclone are all optimized.

Anyone wanting to delve into the subject in a little more detail, but not so detailed as to be difficult to understand, should take a quick look at the following link:

Hydrocyclone Working Principle (911metallurgist.com)

Hydrocyclone is a term that really tells us what happens with this particular piece of equipment.  A water suspension of minerals is pumped, under pressure, into a device where this slurry is separated by the use of a "cyclone" ( that is where the vortex comes into play ) into big particles and small particles.  "Hydro" in reference to water and "Cyclone" in refernce to the internal vortex created inside the separating device.

Bottom line:  The addition of Sawtooth Mining Company, LLC has undoubtedly resulted in suggestions and maybe even requirements for modifying the original plans for processing of the lithium clay into lithium hydroxide and lithium carbonate.  So, what modifications in that processing have been proposed.  More to the point:  What modifications have been adopted?

Thanks, Clifford, for bringing up the Reno Lab again and thanks to AXP for mentioning the addition of this old technology, the hydrocyclone, as an addition to the processing originally proposed back in the 1 August 2018 PFS.  

Okiedo