Analysts who are critical of the potential merger between Rio Tinto (RIO.US) and Glencore have expressed pessimistic views about the deal.

According to reports from overseas media, executives from Rio Tinto (RIO.US) and Glencore discussed a potential merger for several months, which could be the largest deal in mining history. Negotiations are not active and it is unclear whether they can be resumed, but the willingness of the two companies to engage in long-term negotiations surprised many people in the mining industry.

Analysts were almost universally critical of the potential deal, with CreditSights analysts summarizing succinctly: "Is this for real?"

CreditSights said: "Culturally, Rio Tinto has traditionally been seen as conservative and stable, while Glencore is known for being aggressive and pushing the limits of business." However, if the deal becomes a reality, it may ripple in the mining industry, "which could bring back BHP Group and Anglo American."

Analysts at MKP Advisors wrote that the merger seemed to be a strange strategic move, considering the limited overlap between the two companies and their different strategies. They also added that Rio Tinto would be especially hard to sell the deal to its shareholders, considering the deal contradicts all the information it has previously conveyed to investors.

According to MKP, Glencore's copper assets are the only real target commodity that fits Rio Tinto's model, even so, the merger seems to be an expensive and roundabout way to acquire such assets, and Rio Tinto seems not interested in Glencore's secondary assets.

Dan Coatsworth of AJ Bell said the two miners may be incompatible because Rio Tinto is an environmentally responsible miner, while Glencore's "profit-at-all-costs" approach has earned it the nickname "the bad boy of the mining industry."

Berenberg analysts wrote that a merger is unlikely, and the negotiations between the two companies may be a normal business process, and added that any deal could be an all-stock transaction, but Rio Tinto seems unwilling to pay a meaningful premium for Glencore's assets.