Yes the translation is fine and you don't seem to have missed much. But this only covers one interpretation and could to some extent be adapted for some others. Maybe a better translation might be "rock waste" as you may deduce from the later explanations and interpretations.
Note that imam al-Qurtobi -see here in Arabic- when introducing this verse pointed at an example Allah made here: Musa () was keen to see Allah, and Allah told him to look at the mount if the mount would stand still Musa would be able tom see Allah and if not Musa wouldn't be able to see Him or stand looking at Him and as the Allah appeared to the mount it couldn't stand still and. Allah's appearance here does not necessarily mean a full appearance, but it is like if you want to show a sword by lifting a part of it from the scabbard. Qadi 'Iyad mentioned an interpretation of abu Bakr ibn Tayyib saying that the mount saw Allah and became a heap of dust (or soil according to ibn 'Abbas) or (big or a big heap of) sand (According to 'Atiya al-'Awfi) and Musa () saw Allah and fell down unconscious.
Ibn Jarir at-Tabari even considered the mount as a much "stronger" being that couldn't resist to Allah's appearance and it's glory as mentioned in his tafsir.
The actual meaning is that Allah made it collapse so that it became as high as if there was no mount at the place before and the whole mount was reduced or better reduced or teared itself fainting or -"by acting forces" or "Allah's power" or His "nur/light"- to some dust or rock waste covering the soil.
In the sunnah of the prophet () you may read:
"Hammad bin Salamah narrated to us, from Thabit, from Anas, that the Prophet (ﷺ) recited this Ayah: So when his Lord appeared to the mountain, He made it collapse to dust (7:143) - Hammad said: "Like this." Sulaiman held his thumb over the tip of his finger on the right hand (so that only the tip of one finger was protruding) - and he [the Prophet (ﷺ)] said: "So the mountain fainted. 'And Musa fell down unconscious.'" (Jami' at-Tirmidhi)
This tradition was also quoted in Musnad Ahmad and in the Tafssir of ibn Kathir -see here in qtafssir-.
Imam ibn Jarir at-Tabari commented the verse as follows -in his tafssir see here in Arabic-:
In the following I'll translate from Arabic as the interpretation is mine take it with the necessary care!
قال أبو جعفر : يقول تعالى ذكره : فلما اطلع الرب للجبل ، جعل الله الجبل دكا ، أي : مستويا بالأرض
Abu Ja'afar said: the Almighty in Speech (Remembrance?) says: when the Lord appeared to the mountain. Allah made the mountain turn to dust: means it got as flat as the earth.
The main point is the interpretation or translation of
The Arabic verb دَكَّ in Arabic means to compress, ram, serry, cram etc.
So the word dakkan refers to dakk دَكٌ or الدَك: what remained of the mountain after this action or otherwise said:
the result of the compressing, collapsing or "forceful" reduction or disappearance of the mountain.
Which was also interpreted as fainting of the mount without any mentioning of an acting force. Note that only a few interpretation actually mentioned the material of this dakk.
Ibn Jarir later quoted several narrations and interpretations of the verse: