What are the practical uses of lahar, the grey stuff from volcanoes?

yup, mt. pinatubo indeed..a very historic volcanic eruption which affected the whole world..its immediate good effect is that it prevented global warming by blocking uv rays during the eruption and it really had a big impact on the climatic status up to now..the dissipated ashes (lahar) is presently hauled to nearby provinces as a raw material for making clay pots, tiles, and damp fillings.