Yesterday, a man sitting on ground covered in his friend's blood was testimony to the danger of such an enterprise. His friend was shot, along with two other Muslims, by a sniper from the east bank of the river - the Muslim side of Mostar.
One man died, a victim of his own people. But the other, dazed and shaken by the trauma of having to carry his wounded friend out of the killing zone, washed his hands with water from a wine bottle and went back to shovelling. He had little choice: he is one of at least 2,000 Muslim prisoners believed to be used by the Croats as forced labour.
Such treatment violates the Geneva Conventions; and the Muslims on the other side of the divided city abuse their prisoners in a similar fashion in this increasingly dirty war.
Their loyalty in question since war between the Bosnian Croat HVO and the Muslim-led Bosnian army broke out last spring, thousands of Muslim men of fighting age in Croat-held areas have been arrested; most of their families have been herded under sniper fire across the east bank into what has become the Muslim ghetto.
The men working the sand mounds yesterday were dressed in T-shirts and shorts or dirty trousers. All were dusty from their back-breaking work. They were not supposed to talk to foreign reporters but at one point some prisoners rushed up to me to beg for cigarettes. A few men looked thin; their skinny legs poking out from under shorts made them look like large flightless storks.
Soldiers barked instructions and the men kept shovelling. There was an unseasonal chill in the air, leading Velica Kokotovic, a Bosnian Serb who lives with her husband on the front line, to offer one of the thinner prisoners a jumper. 'It's not that I am sorry for them. No. It is just that it was a bit chilly. that's all,' she said.
'They must work hard,' interrupted a Croatian onlooker. 'If they don't work they get beaten.'
One prisoner, a 40-year-old electrician, whispered to a journalist from a Slovene newspaper that he was not badly treated and was fed regularly, but with small portions. He then told how he was arrested three months ago and his family was forced out of their flat on the west side of the city. He believes his wife and teenage son are staying with Croatian friends not far from his detention centre, but he was not sure if they knew he was alive.
The Bosnian government in Sarajevo estimates that since the fighting in Mostar erupted on 9 May, at least 107 Muslim civilians have been killed and 458 injured, some by roving bands of Croatian 'punishment' squads operating in the area. Captured Muslims are put to work, often in dangerous situations.
Sniper fire was not particularly fierce yesterday along the labyrinth of tunnels, shelled buildings and sand-bagged bunkers that makes up the front line cutting through the heart of Mostar. But Muslims were shooting across the river in spite of a supposed ceasefire. The Croats were using Muslim prisoners to help shore up their positions.
The Croatian HVO soldiers and officers manning the front line and supervising the prisoners were not keen to have a reporter and photographer watching, especially so soon after one prisoner had been killed. 'We do not want you on this front line. Now leave while you still can with your equipment,' said one officer.
However, the Croats are keen to avoid negative publicity and try to focus outsiders' attention on the treatment of Croats held by Muslims on the other side of town to justify their own actions. 'The Muslims use Croats as human shields. These shields are civilians who lived on that side of town but who are now actual prisoners,' said Nikola Raguz, a deputy HVO commander in charge of propaganda in Mostar. The use of Croats has been confirmed by reporters who visited the east bank recently.
Before the war devastated this once stately city, Mostar was a cosmopolitan town of about 130,000 people, where Croats and Muslims were balanced by a little leavening of Serbs. There are few remnants of those days, but some can still be found, ironically on the same front line.
Ekrat, 25, a former mechanic, is one of several dozen Muslims and Serbs serving in the HVO. Ekrat, who fights alongside his Croatian friends under sniper fire from across the river, said: 'A lot has happened here that I don't understand. But I am here with my friends fighting for my town and hoping that all this will end soon.'Reuse content