Correct (except for the omission of "the"), but contrast it with this sentence:
I am going to go to the store in an hour.
Я собираюсь пойти в магазин через час.
Here, "going to" is not the present-progressive tense of to go (as in "I'm going to the store"). It's an auxiliary verb marking the future, and thus "I'm going to go" is roughly the same as "I will go".
P.S.But in English, it is quite possible to say "The stone is going to fall from the mountain".
Absolutely correct, Bob. Here, going to simply expresses the "near-futureness" of the action, even though a stone cannot feel an intention to fall.
P.P.S.Russian "собираться" does not even guarantee the event will actually happen. The one who "собирается" can change his mind in some future.
In such cases, "to be thinking about doing something" would be a better translation than "going to do something":
Ты знаешь английский язык?
- Нет. Я собирался его выучить. Но так и не собрался.
Do you know English?
No, I was thinking about studying English, but I never got around to it.
Wooden coins like this one, printed with the nonsense word "TUIT," are sometimes given as humorous gifts.
I finally got around to it. = Наконец я успел сделать это. / Наконец я начал заниматься этим.
I finally got a round "TUIT" = Наконец я получил круглую штуку "TUIT".