Translation:Left of him is another mountain.
It does seem to me that "left of it" would be okay in some circumstances. Suppose the context was such that they were talking about a mountain (masculine noun) and the sentence was saying that left of that mountain stands a further mountain. In English, we would then say "left of it", but in German wouldn't they say "Links von ihm..."? I'm really not sure, and I would welcome help on this.
As a native English speaker I would say "from him" or "of him". You want the listener to take the point of view of the man and from that position see the mountain. "Left from him is another mountain". You want the listener to look to the left of the man. "Left of him is another mountain." Von translates as "of or from" so I figure either "of or from" should work as an english translation. In English direction is more exact if it is from or to something, degrees or a cardinal direction . The mountain is a fixed direction from the man. Most people are not exact when giving direction and do not understand this concept. "Turn left" is east if you are going south and west if you are going north.
@luciohdf : I'm using ihn with accusative to mean 'him', and ihm with dative to mean 'with him' or 'to him', etc.
Check this out also: http://canoo.net/inflection/er:Pron:Personal:3rd:SG:M