Two near-perfect black cones rise from the farmland between Ruitz, Maisnil-lès-Ruitz and Haillicourt, and once you have spotted them you will keep seeing them for miles. These twin terrils, the spoil heaps of former coal pits, are among the tallest in the Nord-Pas de Calais basin and have become something of a regional emblem. They look volcanic, which in a way they are: shale and waste rock tipped there for decades by the mining companies, slowly settling into steep, smooth pyramids that turn purple-grey in rain and almost silver in bright sun.
What fascinates naturalists is how quickly nature moved back in. The dark surfaces heat up in summer far more than the surrounding fields, creating a warm, dry microclimate where plants and insects normally found much further south can survive. Birch, buddleia and pioneer grasses colonise the lower slopes, and some heaps even host rare lizards and orchids. Many terrils in the basin are now protected green spaces, crossed by walking paths and occasionally used for sport, and they belong to the mining landscape listed by UNESCO in 2012.
The roads around here roll a little more than in the flatter east of the basin, because you are on the edge of the Artois hills. Lanes run between small towns and big open fields of wheat, beet and potatoes, with modest climbs and a few genuinely enjoyable bends heading west toward the higher ground. Surfaces are generally good, but farm traffic leaves mud on the road in harvest season, and cobbles survive in some town centres. Wind is the constant companion in this open country. The best views of the twins come from a few kilometres out, from the west or south, when the low sun catches their flanks.
For the practical side, Haillicourt and the neighbouring towns of Bruay-la-Buissière and Barlin have fuel, bakeries, supermarkets and the inevitable friteries. There is no café on top of a terril, of course, and climbing these steep heaps is often forbidden for safety reasons, so look for marked paths rather than scrambling. Take a slow loop around them instead, stop somewhere on a farm track with the engine off, and listen to the larks over the fields. It is a strange pleasure, admiring a pile of mining waste, but these two have earned it.