Published in the August 2005 American Longwall Magazine

It began with the green movement in the 1960s and today it’s about keeping your recyclable glass separate from your plastics. Society today is environmentally aware, with major ramifications for the coal industry.

While global warming is grabbing world headlines, subsidence from longwall mining is grabbing local paper headlines. Communities are very much aware and pro-active when it comes to subsidence from longwall mining. Several high profile subsidence cases of late have influenced public opinion, and as an off-shoot, governments have implemented tougher regulations, especially where longwall mining can alter surface hydrology.

This is not to say coal companies and mines aren’t striving towards environmental accountability. Consultancy Hatch Mott MacDonald (HMM) recently worked with a Pennsylvania longwall mine operator to implement a structured approach to managing hydrological monitoring data collected over a longwall. The result was not only an approach that met regulations, but one that exceeded requirements and was adaptable to regulatory changes.

Longwall mine operators seeking mine permits often need to inventory hydrologic features to be undermined and collect pre- and post-mining data to determine if even temporary hydrologic changes have occurred. According to HMM, using a structured approach to managing hydrologic data allows mine operators to proactively address current and anticipated future regulatory requirements to successfully obtain a permit to operate the mine.

With this in mind, HMM proposed a program that would assist in cost-effective collection of hydrologic data over longwall operations in Pennsylvania.

An eight-step plan was devised by the operator and consultant. To begin with, team members were interviewed with the purpose of identifying the data to be collected and to examine collection and reporting methods. Next, the data process was reviewed, looking at how the data was to be collected, formatted and used.

A systems review process then identified and evaluated the different systems that would be used to collect and store project data – such as global positioning, flow meters, AutoCAD, and more. The needs assessment process then summarized the findings in an assessment database.

A series of workshops were performed to identify the program needs and to build a consensus on data collection and management. The results of the workshops generated a focused set of needs in staffing, what pieces of data for each monitoring site were needed, the equipment needed to collect the data, and the application needed to collect and store the data.

Once all the steps were completed a program that could confidently meet the objectives was developed and the pilot phase was launched. This included taking stream flow and well measurements and collecting water samples. Biological data including establishing fish and habitat indices and mapping the wetlands.

Establishing logistics was a big task for the team – large areas and an array of personnel meant monitoring had to be meticulously scheduled. The frequency of monitoring was also varied – frequent when the area was directly undermined, as changes can occur quickly, and less frequently pre- or post-mining in order to determine the degree of recovery flow, biology, or chemistry, to pre-mining levels.

To manage the data on a constant basis, HMM developed a custom computer program for data collection and entry that was also accessible by the client, multiple consultants in multiple offices, and from remote locations.

The program developed - web-based environmental data management system (eDMS) – tracked all the data related to a site, any visits to the site, and all surface water, well and biological sampling.

Making the program responsive and adaptable was essential. The program evolved from monitoring flow at several points along a stream to examining the entire undermined length of stream, giving a complete hydrologic knowledge of pre-existing stream conditions and the ability to distinguish between natural changes and mining-related changes.

Article adapted from “A structured approach to managing hydrologic monitoring data collected over longwall coal mines” by Kimberly Lottig, William Andrews and Kenneth Johnson, presented at Longwall USA coal show.