# 162

Dear Tafuteni Nicholaus Chusi, Mouhamed Bayane Bouraima, Morteza Yazdani, Stefan Jovčić, Violeta Doval Hernández

I read your paper:

Addressing the Challenges Facing Developing Countries in the Mining Sector: Moving Towards Sustainability

My comments:

1- In page 4 you say” They involve comparing criteria through Pairwise Comparisons (PCs). The AHP method gathers expert opinions to rank criteria on a 1–9 scale, determining their significance [18]. SWARA eliminates less significant criteria and ranks the most important ones [19]. BWM compares criteria using best and worst references, mitigating bias [20]. FUCOM compares each criterion to others using a decimal or integer scale in PCs. The FullEX method differs from other subjective approaches”

I am afraid that I do not concur with any of your statements, with due respect to your and other cited authors’ opinions, these are my points:

· Pair-wise comparisons has been since long criticized by many scholars to be used in MCDM, because the arbitrary assigning relative importance of criteria. Of course, it is legit to establish a preference between two criteria, but it is absurd assigning a value to those preferences. This procedure does not have neither mathematical support nor a common-sense judgement. Suppose you have criteria love and tenderness, can you honestly put a value of preference?

Or between education and support to students? Or using steel or concrete in construction?

According to AHP procedure, a DM acts based on his mood, intuition, wishes and feelings, not in facts or in reasoning. Perhaps the method is good for personal problems as selecting a restaurant to dine, but not for real-life scenarios involving perhaps millions of people. In so doing, the DM or a group are voting representing those millions, and that were not consulted. On what authority the group can vote for them? The Arrow’s Impossibility Theorem defines that as tyranny. Years ago, I had my own discussions with Thomas Saaty about this subject.

· When SWARA eliminates the less significant criteria it is solving a different problem from the original. If the DM or stakeholders put them, they had their reasons. Maybe their significance is small, but the DM never knows how they interact with the other criteria. Therefore, in my opinion, it is mistake

· Same for BWM. On what grounds the DM knows which are the best and worst references? By intuition? The real-world does not work on that premise

· Same for FUCUM. On what mathematical grounds is this procedure supported? There is none

· Similar for FullEX since it is based on experts’ subjective values. In addition, and please consider my ignorance, in that as far as I understand this method is related to city logistics, and your paper is about mining. Of course, there must be an explanation, but I believe that it should be explicated in the paper. Why a reader must accept what an author says?

2- Page 4 “Their findings suggest that mining doesn’t align with just one SDG but impacts multiple goals simultaneously”

I agree in a 100% with your statement, and this is one of the reasons by which most MCDM methods cannot solve real problems, only approximations or proxies, because they consider that criteria are independent events, and one does not affect or impact the others. By the way, this is one of the main axioms in System Engineering. Try to build a car analyzing independently its different components, like engine, transmission, exhaust system, body, tires; you cannot, because each one of these elements participates in the design of the engine. The same in SDGs if you apply MCDM. How many methods follows this obvious notion? Almost none,except Mathematical Programming.

3- Please correct error in title in Section 2.2.

4- I tried to follow your reasoning related the procedure for FullEX, I read it several times and could not understand the procedure. It is confusing, helped by the absence of explanation on some terms, for instance

· Page 7 “The triangular form arises from gradual criterion comparison’”

According to your explanation “The triangular form arises from gradual criterion comparison, excluding the previously compared criterion in each step”

Sorry, for me that is unintelligible

· What are YE and DE? In equation 1?

· What is W in equation 2?

· What is V in equation 3?

· What is r in equation 4?

· What is Vmax in equation 5?

· What is y in equation 6?

· What is K in equation 7?

Table 3 It is in my opinion, a good set of criteria

In page 9, Fig 2, what are challenges?

5- Pag 11, Section 5.2. Where did you explain that an expert was omitted, and why?

As you can see, it is quite difficult to understand a method when the author assumes that a reader must know in detail the scenario. If you allow me, I would suggest to create a glossary of expressions and lettering for variables at the beginning of the paper.

I stop here, but I hope that my comments may be useful to you

Nolberto Munier