Leaching Agent Selection Guide

Selection without a parameter table

A selection guide usually presents a table of parameters, but this guide does not, because no parameter table was provided by the sources used for this site. Publishing a table assembled from third-party pages would present unverified figures as though they had been checked, and that would mislead a buyer at exactly the moment when accuracy matters most. Instead, this guide names the dimensions on which a selection should be made, and turns each dimension into a question that can be put to the company for the ore actually being considered.

The dimensions are the ore, the process step, the form of the question, and the documents that should be requested. Each dimension is explained below in general terms, and each explanation ends with the form of question that belongs to it. A buyer who works through the dimensions in order will arrive at an inquiry that the company can answer, rather than at a comparison that rests on figures nobody has verified for that ore.

Dimensions to compare

The first dimension is the ore itself: its identity, its preparation history, and the step at which an agent is being considered. The second dimension is the approach: whether the question concerns a non-cyanide approach, a replacement for an existing approach, or a general selection between approaches, and what the company proposes for that ore and step. The third dimension is the evidence: what information, if any, the company can provide for that combination, and in what form it can be provided.

The fourth dimension is the practical arrangement: the minimum order quantity, the lead time, and the shipping arrangement, all asked as questions rather than assumed as figures. The fifth dimension is the document: which certificate or document, if any, is needed, and for what purpose. A selection that covers all five dimensions is a selection that can be checked, while a selection that covers only the first dimension is a guess dressed as a comparison.

From dimensions to a message

A selection inquiry should take the dimensions in order and answer each one briefly, in the buyer's own words, before asking the company to respond. It should say what is known, what is not known, and what would count as a useful answer. That structure helps the company reply to the ore and step actually named, and it helps the buyer check whether the reply covers every dimension or only some of them.

A selection inquiry should also state whether the comparison is between named approaches or between an approach and a general requirement, because those are different questions. A comparison between named approaches needs the names and the terms of the comparison, while a comparison against a requirement needs the requirement stated plainly. Either form is acceptable, but the form should be clear in the message itself, not left for the reader to infer.

Selection as elimination, not as ranking

Selection is often presented as a ranking, with one approach placed above the others, but for a particular ore it is more usefully thought of as elimination. Each approach is tested against the ore, the step, and the documents needed, and approaches that do not fit those particulars are set aside, until the approaches that remain are those that fit the case actually being considered. Elimination has an advantage over ranking: it does not require a universal order that holds for every ore, and it does not pretend that a general ranking answers a particular question.

Elimination also keeps the inquiry honest, because it forces the buyer to state the criteria for setting an approach aside, rather than relying on a general preference. A criterion stated plainly, such as a step that an approach does not cover, or a document that cannot be provided for a particular purpose, can be checked and, if wrong, corrected. A preference stated without criteria cannot be checked, and it will usually survive longer than it should, because nobody can show why it should be set aside.