Mine Site Environmental Monitoring

Planning, operating and decommissioning mine sites require detailed long term environmental monitoring and evaluation. Generally a new mine will not be approved without a detailed environmental monitoring plan, which would be approved by government authorities with an overall objective being that the environment is not changed in any way as a result of the mining operations. As mines may operate for several years, there would be a need to monitor the different stages.

Application Detail

Firstly there will be the need to monitor environmental parameters before any operations commence to determine a baseline for the local environment. Secondly, when the mine is operating, there will be environmental parameter limits which must not be exceeded during the operations. These parameters need to be monitored and recorded. Furthermore, alarms for out of limits conditions should be set up and out of limits occurrences recorder and analysed.
Finally, when the mining operations have been completed, there is a need to rehabilitate the mine site and restore the mine area to its original condition. It is important to monitor the mine site for a period of years to make sure that the site is recovering as predicted.

Mostly, there will be a requirement to monitor the weather in the area. For example, weather station tier 2 can be used to record the ambient conditions, like wind speed and direction, humidity and temperature and solar radiation. Collected data helps establish general wind conditions around the mine. This analysis then assists in creating processes that should prevent mine emissions to be carried, by the wind, to areas of population, such as a local town or city. To get good readings for the local area, there may be the need for multiple weather stations to be installed, for instance, one at the plant and one at each perimeter fence of the facility.

Unidata supplies various weather station instruments, either a multifunction ultrasonic weather transmitter, which is very convenient to install, or a separate discrete weather instruments. For this application, the multifunction ultrasonic weather transmitter would be the best choice. As well as weather, there may be a need to monitor evaporation, especially important in uranium mines. All Unidata’s evaporation systems measure how much water evaporates from a US Class A evaporation pan by measuring the water level in an adjoining still well.

The simplest model, known as the 6529-1 Evaporation Monitoring System, comprises of an evaporation pan with a bird and leaf cover and a manual measurement system.
Furthermore, there may be a requirement to add additional instruments to measure the presence of noxious gases and dust. There are many manufacturers of gas monitoring equipment. One such manufacturer is Draeger that offers sensors that measure noxious gases such as CO, CO2, NO, H2S, SO2 as well as O2 and N. These instruments typically provide a 4-20mA analog or a Modbus output which can be read by Neon Remote Logger routinely, perhaps every minute and then routinely send the data to the Neon Server every 15 minutes.

Monitoring of the water table (Groundwater) in the area will also be needed. Groundwater depth (often called bore hole monitoring) is measured with a small diameter sensor deep in an observation bore hole. Water depth can be measured with a pressure sensor lowered down the bore hole and immersed in the water. This is call hydrostatic depth method. Alternatively a standard float-and-pulley sensor system with a small float and a pulley at the top of the bore hole can also be used to measure depth. These systems are typically installed in existing bores, perhaps with a diameter of 100 to 200mm and a depth of 5 to 50 meters.

Water quality measurements for any local streams or mine site process outflows is important. To comply with environmental protection laws, water quality monitoring instruments should be used for regular water quality audits of any outflows. These instruments can also be connected with a Neon Remote Logger to scan the instruments inputs, perhaps every few seconds and immediately alert a central Neon Server if there are any out of limits conditions. Logger can send routine data to the Neon Server, utilising either cell phone, satellite or plant Ethernet or WiFi network.

Finally, all of the environmental measurements would be recorded on the central Neon Server system, which is web based, so the data can be accessed from anywhere on the internet. The data could also be exported, via several methods, perhaps each minute, or each hour, or each day to any central environmental monitoring compliance system as required.