Cement, Energy and Environment

a throughout of 100 000 t / a to meet the future demand for special cements over the coming years. Over 100 mix formulations and sequences can be preset and s tored. Direct production of special mixes for particular requirements is also possible on a "just in time" basis. Courtesy: ZKG International, No. 12/2001 (Vol. 54) 1 Pp 655-57. WHAT IS "MOBILE'? Brian Flynn, MMD. UK. The dictionary definition of the world mobile is 'movable or easilymoved', but what it means to mine operators with respect to crushing systems varies almost as much as the materials that are extracted. One of the first mobile systems supplied by the MMD Group of Companies was for a lignite operation in northern Spain. The existing mobile crusher employed to handle overburden in the mine was a 1000 tph gyratory unit with a separate truck bridge. These units were moved using a 600 t capacity tracked transporter and each took approximately 3 days to relocate to the next level down (approximately 20m). The method of operation at that time was to work on two levels, one in the winter and a lower level in the summer due to the level of the water table at the quarry. To achieve this, a series of fixed and quick assembly belt units were used, which were erected in advance of the breaking units so that the change from one location to the next required the minimum disruption to production. The latest development has been the purchase of a track mounted system based on the 1000 series sizer fitted with three tooth rotors, which can h andle the bigger harder lumps encountered in the bottom level of the quarry. The most recent mobile unit supplied by MMD was to a lime-stone quarry in Spa in. It has a deposit in a hillside, which means they have a high multibench system. Material is pushed from the higher bench levels to the bottom bench. The definition of mobile means the comple te plant can be relocated within the quarry in one day. There are a number of key features that n1ake this possible. The primary unit is a wheel mounted 750 system fitted with three tooth rotors and powered by a diesel engine, which is not unusual where the mains power supply is limited. What of the future? The company has designed cu'1d built a fully mobile unit,which has a design capacity of 10 000 tph with an approximate weight of 1500 t. It combines an apron plate feeder, sizer and slewing elevating discharge conveyor mounted on a turn table. The whole unit is mounted on tracks, which allow it to move in conjunction with the large rope shovel feeding the unit. This unit is to replace a bucket wheel excavator and will discharge onto an existing belt conveyor systern. Maybe now an alternative definition of 'mobile' should be 'n ot fixed' . Courtesy : World Cement Apr. 2002 Pp 92-94, Enquiry no: 20 Fax :+44(0)1252718992 E-m ail: mail@ worldcement.com Web: www. worldcen1ent. com SEEING THE PROCESS FROM A DIFFERENT ANGLE F. L. Smidth's Customer services Department introduced a new service concept under the name of Process Maintenance Technology (PMT) (see Highlights October 2000). Under the new concept each customer is assigned a