The British police team knew their work here on the Algarve wouldn't be easy, but it seems it's even tougher than they'd thought.
A search, originally planned for just six days may now take a fortnight.
We don't know why they've doubled the timeframe. It could be that the work is simply harder than predicted, they're scouring baked, rocky, scrub covered terrain, after all.
Or it could be that there are more "places of interest" on this wasteground than satellite images suggested.
So far, two specific locations have drawn close attention. Officers uncovered a well concealed hole in the ground on the second day of their search. It had been hidden beneath sheets of corrugated iron and a layer of topsoil. The mouth of the hole is supported by planks of wood, like the entrance to a tunnel.
A tent was erected to preserve the site and police in forensics suits came and went from there yesterday.
Today, they seem less interested in the location. There's a suggestion it may have been a "den" used by local children in the past.
But the second spot they've identified is still keeping officers busy. Ground penetrating radar equipment picked up an image beneath the soil there yesterday. Forensic teams began work on the spot late in the afternoon and even the most senior detectives stayed on into the evening, supervising the operation.
Today, a team is still at work on the spot. Intermittently, they emerge to take buckets back to their vans. Samples, perhaps, for inspection.
Sources inside the investigation tell me the discovery is unlikely to be the "smoking gun" which has eluded police for seven years, but they certainly believe something is worthy of close attention.
Elsewhere on this vast scrubland teams continue to clear undergrowth and rake away at the soil. It's tough work in the baking heat but they're attacking it with just the same commitment they showed on day one.
Sniffer dogs have been out again this morning, scampering in and out of the bushes, looking to pick up a scent.
From their base at the highest point of the site, detectives scour the area with binoculars and Portuguese mounted officers patrol the perimeter on horseback. This is not an operation moving at breakneck speed, more of a slow, determined grind.
Frustratingly, we're receiving no updates from the teams here, no progress reports at all. The British taxpayer would be entitled to expect at least some information, perhaps, given the search is being funded from the public purse, but Scotland Yard insists its hands are tied. This is, officially, a Portuguese police operation and the law here forbids officers from talking about an ongoing inquiry.
So it may be that for another week or more we watch this meticulous search continue, fascinated by the methods the police are employing but unable to tell whether any of this is taking them even a small step closer to finding Madeleine McCann.