Preventing the Disasters that National Miner's Day Memorialize

Protecting hydraulic roof support shields from contamination

December 17, 2019 | 5 minute read


Earlier this month, John Crane commemorated the 10th Anniversary of National Miner's Day, created in memory of the Monongah Mining Disaster, one of the worst mining accidents to date in the United States.

On December 6, 1907, an explosion destroyed the supports and ventilation shafts in the mine, killing 362 miners. Many other explosions happened that year, making it the deadliest mining year in America with more than 3,000 deaths.

Though safety statistics have greatly improved since 1907, mining safety continues to be a top concern worldwide, and one that we take very seriously. With decades of experience serving the mining and minerals industries, we understand the need for greater equipment reliability and maximum performance in harsh environments.

Some of the largest areas of difficulty for underground mining continue to be dust, vibration and noise.

Through our Seebach filtration products, John Crane tackles the area of dust and other contamination that can cause machinery to break down and hazardous conditions to develop.

The hardness of the solids being transported in the slurry, in relation to the seal faces, needs to considered. If the solids are harder than stainless steel, for example, they will likely be harder than the carbon seal faces, resulting in excessive wear. Making the seal components and pump elements harder than the solids in the slurry is a critical design consideration.

Outlining the Issue

In underground mining, all excavated hollow spaces must be supported against the soil or rock layers above them to prevent potentially catastrophic collapses on people and machinery.

Around the world, hydraulically operated, self-propelled roof support shields are used, which follow the mining machine and are directly adjusted to the respective height of the seam. Depending on the length of the shield alignment these supports can be controlled hydraulically, electro-hydraulically or electrically.

Three types of liquids are needed to operate the machines and plants, two of which are filtered at different pressure levels—water and emulsion.

At the beginning of the process is a large water tank and a concentrate tank where the emulsion is prepared in a mixing station. The concentrate serves to protect the sensitive following components in the liquid circuit against corrosion. Most of the emulsion and water then pass through pump stations to their end users. Water travels to the spraying systems, and the emulsion to the shields or shearer loaders. After this, it is returned to the circuit via tank and return lines.

How We Improve the Process

Different mine environments call for a wide range of filtration needs, and we have the family of products to support every type.

All hydraulic fluids used in the roof support shields are continuously filtered. The high quality of the liquid is intended to ensure a long service life for expensive plant technology.

This is done by in-line filters and back-flush filters which are applied directly at the point of use. As the name indicates, last chance filters offer the last opportunity for filtration directly prior to the inflow into the component to be protected. They are installed into the pressure pipe directly in front of the control valves. In addition to the last chance filters, bypass filters are used to protect the fluid in hydraulic circuits. This means that all valves and sensitive components are protected against impurities that could cause abrasion or blockages.

The selection of filters and the type of back-flushing are individually adapted to the required face height.

Why Us

John Crane, through its filtration portfolio of Seebach filters, has been in the mining and hydraulic filters industry since the 1980s, and is considered an industry leader in mining and power generation. The company Deutsche Steinkohle was the first Seebach customer in the field of underground mining. The constantly growing demand for safety was the reason for the rapid development of this technology.

Many distributors of Seebach products speak to the quality control Seebach is known for, including the best materials, the most stringent testing practices and a commitment to always improving.

 Beautiful sunset over a mining site

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