I agree that this sentence would appear to be connected to the Archaeology profession in Warcraft but I would be tempted to say that the word "artifact" is not needed here and the full sentence could be translated as:

"I unsummoned the mount and continued on foot"

In this sentence, it seems to me that "в артефакт" means that the player is returning the mount to his inventory, rather than reverting it back to an artifact as originally found. The word "unsummon" implies this meaning without the need for the word "artifact".

From my understanding of the Archaeology profession, players collect fragments and once they collect enough fragments, they use them to create an artifact.

The artifact created (in the case of mounts) is an item, which teaches the player to summon the mount. Once the player teaches themselves to summon the mount, the previous inventory item will be replaced by a spell, which will allow the player to summon the mount whenever cast.

One further thought: if an artifact item is bound to a player upon pick up i.e. can be used by one player alone once they pick it up, I cannot think of any benefit to being able to revert the mount back to the original artifact i.e. the ability to learn the spell. They would already have learned it and would not be able to pass it on to any other player since it is a bound item (if that makes sense!)



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Note added at 6 days (2013-10-28 11:18:54 GMT) Post-grading
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You're very welcome, Irène - happy to help!