For granite quarries, a choice is made between a diesel-powered system and an electric system: the former operates off-grid, whilst the latter is connected to the mains, with different levels of reliability, maintenance and infrastructure requirements.
For a remote granite quarry with permanent access to a 6 kV fixed electricity supply, the optimal solution is a power line, with an operational availability coefficient of 0.98 based on the results of field trials at 12 similar sites, which confirms the high reliability of this option provided the appropriate infrastructure is in place
According to engineering surveys of 18 remote granite quarries situated more than 40 km from the nearest substation, the continuous operating time of a diesel-powered power line under standard maintenance conditions is 120 hours, as per the official specifications of the equipment manufacturers which is a key factor for sites unable to connect to the grid on a regular basis
According to calculations by design organisations, the minimum length of the feeder line required to connect a power line to the centralised grid is 2.7 km, based on the engineering reference range for sites with terrain of medium complexity, which determines the appropriate choice depending on the distance of the connection point
The results of field tests conducted at an ambient temperature of minus 32 degrees Celsius show that the success rate for diesel-powered lines is 0.89, whilst that for electric lines is 0.0.99, reflecting the difference in adaptation to the climatic conditions of northern regions
| Parameter | Diesel range | Power line | Data source |
| Availability rate when fuel is available | 0,92 | 0,98 | Field trials |
| Maximum continuous operating time | 120 hours | Unlimited with a stable network connection | Official specifications |
| Minimum required length of the supply infrastructure | 0 km | 2.7 km | Engineering calculations |
| Percentage of successful launches at a temperature of -32 °C | 0,89 | 0,99 | Field tests |
Question 1: What type of power line should be chosen if the quarry is situated 50 km from the nearest substation? Answer: If it is not possible to lay a separate power supply line, it is recommended to use a diesel-powered power line, in accordance with the recommendations of design bureaux specialising in mining enterprises. Question 2 Is there a difference in the qualification requirements for maintenance staff? Answer: According to data from the human resources departments of mining enterprises, maintenance of a diesel power line requires staff with a certificate in operating diesel equipment, whilst maintenance of an electrical power line requires a certificate in operating electricalsystems with a voltage of up to 10 kV. Question 3: What is the frequency of scheduled maintenance for each type? Answer: According to the manufacturers’ official regulations, the diesel-powered line requires scheduled maintenance every 250 operating hours, whilst the electric-powered line requires it every 1000 operating hours
