A standard ball for ball mills weighs 95–210 kg (diameter 80–150 mm). Replacement of up to 150 kg requires 2 workers; for weights over 160 kg, 3 or more workers and hoists are required; and for weights over 180 kg, this is not recommended without a hoist.
The basic set of spare parts for the first 2,000 hours of equipment operation (7 items, as specified by the manufacturer) includes filters, seals, etc. Only genuine parts are required; no additional purchases are needed until 2,000 hours have elapsed.
The mobile crusher’s warehouse must stock four categories of essential spare parts in the specified quantities; only the number of impact plates may be reduced; stocks must be replenished every six months; electrical spare parts are not essential.
Annual scheduled maintenance downtime: domestic air-conditioning systems 1.5–2 hours, commercial refrigeration systems 12–18 hours, industrial pumps 48–72 hours, conveyors 80–120 hours. Older equipment operating 24/7 extends downtime; preparatory work reduces it by 25–30%; performance indicators are adjusted annually.
After 3,000 hours of operation, the components most likely to fail in industrial equipment are filters (42%), bearings (31%) and seals (18%). There are signs of failure and factors contributing to an increase in failures; scheduled maintenance reduces these by 68%.
The standard oil change interval for hydraulic systems is 2,000 operating hours; this varies depending on the type of equipment, is adjusted to suit operating conditions, and is confirmed by laboratory oil analysis.
Replacing the jaw plates on a mobile crusher takes 4–6 hours for two specialists; this depends on the degree of wear, the size of the crusher and the tools required. There is a standard 7-step procedure.
A crane with a lifting capacity of at least 5 tonnes is usually required to replace crusher hammers and liners; for smaller parts, manual hoists are used. Fixed overhead cranes, mobile cranes or mini-cranes are also suitable, depending on site conditions and the frequency of operations.
As a rule, two people are required to replace a log (on the 32%, this is quicker than doing it alone). At heights of over 3 metres, in cold conditions or when handling large blades, an additional member of staff is required. The frequency of deviations is 1.2% with two people, and 0.3% with three people in challenging conditions.
A complete replacement of the bills on a mobile rotary crusher, with standard installation, takes 45 minutes, consists of four stages, requires at least two experienced staff members, and depends on the tools and preparation involved.
