This is the 11116th most frequent Russian word.
горный
"Горный" means "mountain" or "pertaining to mountains."
Here, 'горные' is used as an adjective to describe 'походы' (hikes) that take place in the mountains.
Я люблю горные походы.
I love mountain hiking.
In this sentence, 'горные' describes 'источники' (springs), indicating that the springs are located in mountainous areas.
Горные источники являются источником чистой воды.
Mountain springs are a source of pure water.
Here, 'горные' is part of the term 'горные лыжи', which refers specifically to downhill skiing or alpine skiing.