If We had sent down this Reading upon a mountain, surely you would have seen it split ascender as dust due to awe of not being able to contain Allah; and these examples, We are quoting them for mankind so that they may meditate and reflect.
The Arabic word Quran means "Repeated Reading." However, it is not the Arabic Quran, but Adhikr that is meant for repeated reading. Just as it is mentioned in verse 7:143 that a mountain could not contain Allah, this verse states that if Adhikr—which is the Three-Time Knowledge and the Wise Reminder—had been sent down upon a mountain, no mountain would have been able to contain it.
This does not mean that the mountain would ascend due to being unable to contain the Arabic Quran, but rather, it signifies that the mountain would ascend due to its inability to contain the Rooh (Spirit-Kalimath) of the Book, which is the soul and life of Adhikr, as explained in verse 18:109. See explanations of 16:43-44, 33:72-73, and 41:41-43.