We use a German made Heizohack HM 8-400 wood chipper. This chips to G30/G50 standards and is designed for producing chip especially for boilers, unlike many other chippers that create long shreds of wood that can cause blockages. Thanks to some clever engineering, larger chips are bounced back to be chipped again and the machine can be operated via remote for safety.
Our wood chipper is crane fed fresh uncontaminated virgin wood and outputs directly into our 30m3 skips which are then parked in the kiln for 24 hours before being delivered directly thereafter. At no point during the production process can contaminants enter the chip.