* High hopes for swift advance on Tripoli fade
* Rebels lack proper weapons
* Grad missiles come raining down
By Michael Georgy
BIR AL-GHANAM, Libya, Aug 5 (Reuters) - When Libyan rebels pushed government forces out of a cement plant on the edge of Bir al-Ghanam last month and set up a position about 80 km (50 miles) from Tripoli, victory seemed within reach.
But the men -- who hold the rebel position in the Western Mountains closest to the Libyan capital - are finding it hard to advance just a few hundred metres, let alone reach Muammar Gaddafi's main stronghold.
"When we took over we kept saying 'We will reach Tripoli soon'. We even called our families and said we are so close to Tripoli. Now we don't really predict anymore. We just hope," said a rebel named Mufaat, who asked that his last name not be used to protect his family from reprisals.
Conditions at Bir al-Ghanam highlight the difficulties of trying to tilt the balance of Libya's war in favour of rebels seeking to end Gaddafi's 41-year-long rule.
Lawyers, doctors and students, now dressed in camouflage but still learning to fight on the job, sit at the plant trying to figure out how to get an edge over a well-trained army.
Government forces are located about 2 kilometers away in the town of Bir al-Ghanam.
Anytime the rebels, armed with AK-47 assault rifles, move forward past a mountain ridge, they hit open, rough desert terrain which offers no cover against superior weapons such as mortars and heavy machineguns.
Government forces have spread landmines as well.
"Gaddafi's forces will cut us down if we try to advance," said 22-year-old rebel Mahmoud Abdullah, a student who was inside a tent.
"At first we thought we could advance to Tripoli in a few days or a week.. But there is no way it can happen quickly. Gaddafi's forces are so organised. They often move around at night and flash their car lights as signals. It's hard to predict their movements."
One thing they do often is fire Grad missiles at the rebels.
Sometimes up to 20 land a day, leaving big white explosion marks in the desert cliffs, or large gaping holes like the one in the cement plant.
There are other dangers too. Last Thursday, Gaddafi's forces surrounded the rebels by crossing over nearby mountains. Three rebels were killed in ensuing clashes.
The fighters have little protection, mostly AK-47 assault rifles, or a few government machineguns that were abandoned when they overran the area.
"We don't think there will be much change here as long as we only have these light weapons," said a rebel named Salem, as he tried to repair one of the machineguns and other fighters cleaned bullets with wet pieces of cardboard.
In Libya's Western Mountains, the rebels hold a chain of towns stretching more than 200 km (124 miles) across a bleak plateau from the Tunisian border. They have just captured a few towns and villages in a new offensives.
But as Bir al-Ghanam illustrates, pressing ahead to Tripoli presents far greater challenges.
Rebels spend much of their time praying, hoping the Muslim fasting month of Ramadan will give them strength and, ultimately, victory.
They also need patience. "I am sure we will win. I am so sure that when I got engaged I vowed I would not marry until that tyrant Gaddafi falls," said rebel Muhammad Mukhtar. "I just hope I don't have to wait too long." (Editing by Douglas Hamilton and Gareth Jones)