The mines beneath Bilbao’s asphalt

LAND

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July 2026

Top photo: A view of the Miribilla neighborhood in Bilbao more than half a century ago. Part of that mine is now occupied by the Bilbao Arena sports complex.

Bizkaia’s mining past is plain to see in places such as Gallarta and the surrounding area. What is most striking, however, is that beneath the streets of the young Miribilla neighbourhood, right in the heart of the capital, the echoes of iron still remain.

The hill, now covered by modern buildings and the spectacular Bilbao Arena, rests on a labyrinth of tunnels: those of San Luis and Malaespera mines. From its bowels, 300,000 tonnes of iron ore were extracted annually.

An ore barge in the heart of Bilbao’s Old Town, very close to the San Antón Bridge, a century ago.

The tunnel network stretches for over 20 kilometres across several levels. San Luis is notable for its extraction chambers: vast spaces with spans of up to 20 metres that today resemble underground cathedrals. Malaespera, older and rougher in appearance, connects the mining levels that descend towards the heart of the estuary. The fact that the site was abandoned protected the structures from vandalism and erosion.

The iron never rested. Once out of the mine, the ore was transported down inclined slopes and suspended in cable-hauled wagons towards the estuary. The loading points were concentrated at the docks of Urazurrutia and La Peña. There, the ore was tipped directly onto barges (gabarras), which carried the treasure to the blast furnaces or the ships anchored in the Abra

TOURIST ATTRACTION

According to speleology experts, Bilbao boasts a world-class tourist attraction. They compare these caverns to the major caves open to the public in Cantabria, the coal mines in Wales and the salt mines in Poland.

Opening up San Luis would transform the range of experiences on offer in Bilbao. However, improving access and managing water resources require staggering amounts of investment.

An ore-burning furnace from the old mines, which still stands today just a stone’s throw from Bilbao La Vieja

WEALTH FOR BILBAO AND BIZKAIA

The San Luis and Malaespera mines produced hematite and, above all, siderite. The ore was of exceptional purity, with iron grades exceeding 50%.

Calcite crystals and small veins of pyrite still glisten on their walls, remnants of a geological feast that fuelled the blast furnaces and generated thousands of direct and indirect jobs, as well as an incredible accumulation of wealth.