From Rifugio Toesca, take path 510 uphill to the intersection with track 519 for Porta del Chiot (2197 m).
Then take path 519 which, with repeated hairpin bends, quickly rises up to the small pass, with a splendid view over Val Susa and the ravines of Chianocco and Foresto. Then continue on the 519, a spectacular balcony path up to the short climb that leads to Colle del Mulinas (2265 m). From here you can enjoy the precipitous, near-vertical view down to the Bergerie dell’Orsiera Alpine Dairy, lying on a vast plateau of pastureland.
The path descends gently across the basin where the bergerie is situted, to the recently renovated buildings used as an overnight shelter and a park warden’s hut. From here take the trail eastwards, ignoring the junction with path 514 to the left signposted Pra la Grangia, and ford the stream, to reach path 525 that makes a high traverse of the slope above, before leading into a dense larch wood and finally descending steeply towards the Alpe Toglie (1546 m) mountain pasture.
From the mountain pasture descend along the cart track until the hairpin bend with signs for path 521 (Sentiero dei Franchi), which is clearly marked. This trail runs along a long stretch of ups and downs up to a small pass, beyond which it quickly descends towards the village of Comba (1404 m). Head past this and continue straight. Skirt the meadows at Comba, and descend to the Gerardo stream, which you cross on a rustic bridge, then go up the meadows, to reach the wide grassy valley of Pra Mean, beyond which, after passing a grassy saddle, you reach Rifugio Amprimo.
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As an alternative to the long tour from the Bergerie dell’Orsiera and from Alpe Toglie, you can make the direct descent from Rifugio Toesca to Rifugio Amprimo following path 510 (journey time: 1 hour; total elevation loss: 335 m.) following a very easy and well-marked route that passes near Alpe Balmetta Vecchia.