The rescue operation for Julen, the two-year-old boy who fell down a borehole in Totalán, near Malaga city, went into its 13th day on Friday, with engineers and specialist miners working round the clock.
By 2.30pm on Friday the miners had covered 2.5 metres of the four-metre tunnel they need to dig to connect with the hole where Julen was thought to be. A third blast, with explosives brought in by helicopter from Seville, helped the diggers make progress through the hard rock.
At 8.30pm, with more than three metres of tunnel complete, the Guardia Civil spokesperson stated that a fourth controlled blast was required to break through the last few centimetres of hard rock. Further specialists were flown in by helicopter earlier on Friday to help with the precision of this final controlled explosion.
After hours working in cramped conditions at the bottom of a 60-metre-deep shaft, on Friday morning miners had advanced just a metre and a half in their attempts to tunnel four metres through to the hole Julen fell down, despite initial reports that stated they were half way through.
The miners came up against extremely hard rock, which required the intervention of explosives specialists for the third time since the tunnelling began on Thursday evening.
After days of complications, on Thursday afternoon miners were eventually able to go down into the vertical tunnel drilled parallel to the narrow 100-metre-deep hole the boy fell down on Sunday 13 January.
Working in pairs in 40-minute shifts, specialists from the Asturias Mining Rescue Brigade set about digging a horizontal tunnel from the bottom of the shaft to connect with section of the hole where Julen is thought to be.
This work, using a jackhammer, axe and spades, was expected to take around 24 hours, although the hard rock is slowing down progress. On two occasions during Thursday night and again on Friday morning miners had to resort to explosives specialists to carry out small explosions to aid the digging.
Since Julen's accident was first reported the rescue operation has grown to take the form of an unprecedented feat of emergency civil engineering.
After several options were considered, the specialists decided to drill a new hole, or vertical tunnel, parallel to the original borehole the boy fell down.
Drilling to a depth of more than 70 metres would have been impossible however so first the rescuers excavated the hillside to be able to start at a lower level.
This is the first time in Spain that a tunnel of this size has been dug to a depth of 60 metres.
Drilling, using machinery brought from elsewhere in Spain, began on Saturday, although work was slower than hoped, due to a layer of especially hard rock at a depth of 52 metres reached on Monday morning.
The new hole was completed on Monday evening, leading to the next stage of the operation, the insertion of metal tubing to line the walls of the shaft. This was necessary to allow the special capsule built for the operation to travel up and down the shaft in safety.
The uneven surface of the tunnel walls, however, meant that the tubes came up against two obstructions which had to be dealt with.
Engineers found that the wall of the tunnel that was completed on Monday night had a protrusion that blocked the path of the tubes at a depth of 40 metres. To prevent the tubing from getting stuck, it was removed and the drill set to work again, this time with the cutting teeth on the side to smooth the inside of the walls.
The tubing began to be inserted again early on Wednesday morning, however it came up against another obstruction at a depth of 50 metres.
This time the final ten metres of tubing was narrowed by a team of solderers to avoid the protrusion in the wall of the shaft.
Once completely lined, on Thursday morning safety tests were carried out and a platform built at the entrance to the shaft. A Swedish geolocation firm, the same one that helped locate the 33 Chilean miners in the 2010 accident, then confirmed that the "window" at the bottom of the tube that the miners would work through was properly lined up with the hole where Julen is thought to be.