Umpire analysis between companies
I can't say if this is what is happening with SXL and a company XYZ, but a situation exists where two companies are in the process of coming to some kind of agreement on ore value, and the individual lab analysis between say SLX and Co. XYZ, are too far apart for both parties to be satisfied; then samples are sent to a (third) accredited lab (agreed on by both sides) to perform what is called Umpire Analysis.
The samples are then run in triplicate or even more times (by the Umpire Lab), and what the Umpire's results are...... is the final say. Then ore shipments or agreements can proceed based on the unbiased results. Costs for Umpire analysis are generally shared 50-50 by the two contending companies, but that could also be solely incurred by either company. Umpires are also expensive!
Solver