The predominant method of longwall mining in Australia is longwall retreat system. In retreat longwall mining, two sets of entries are driven between 100 to 250m apart. When the entries have been driven a predetermined length, say two kilometres, they are connected and a rectangular longwall block is outlined. The longwall face is then ...

Large scale underground mining of coal resources in China using longwall mining has resulted in ecological and environment problems, including surface subsidence that is considered serious due to competing interests of prime agricultural lands, food security, and regional economic development. The subsided lands must be rehabilitated …

Longwall retreat mining. Longwall advance mining. There are two methods used to cut a web of coal from the longwall face. The "Bi-Directional" (bi-di) method. The shearer cuts a fresh web of coal each …

About one quarter of the coal produced in Australia is by underground mining methods. The most commonly used underground coal mining methods in Australia are longwall, and room and pillar. This paper provides a detailed review of the two methods, including their advantages and disadvantages, the major geotechnical and operational …

9.1 Introduction. Since the early 1980s, longwall mining has developed into the safest, highest producing and most productive form of underground coal mining, …

Abstract. In 2015, 40 longwall mines provided nearly 60% of the US coal production from underground mining methods. This represents a substantial yet gradual increase from just under 50% over the last 5 years. As a result of this increased production share, the percentage of ground-fall-related fatalities in longwall mines has also increased ...

An alternative method of mining is advance longwall mining. In longwall advancing, the longwall face is set up a short distance from the main development headings.

8.4.2c Longwall Mining. Longwall mining applies to thin, bedded deposits, with uniform thickness and large horizontal extension. Typical deposits are coal seams, potash layers or conglomerates, trona, and gold reefs. …

The type of ventilation system used in a longwall mine is dependant upon the conditions found at each mine. The most influencial factor in the choice of ventilation system is the amount of gas that is present in the mine atmosphere. If the mine is considerably gassy the gas in the mine this has to be removed from the working panel …

Ever-higher requirements from mine operators have led to numerous significant developments in longwall mining technology over the past decades. Mining companies are looking for higher productivity, longer life, a higher degree of automation, full system solutions, increased safety and equipment suitable for extremely high or low seam …

Also, longwall system. See below. longwall mining Longwall mining is an underground method of excavating coal from tabular deposits, as well as soft mineral deposits such …

Cutting Machines - Shearers. Shearers are by far the most commonly used cutting machines, both in Australia and overseas. A shearer consists of a machine body containing electric motors, hydraulic equipment and controls which is mounted over the AFC. Horizontal cutting drums are mounted on the face side of the machine, laced with cutting …

This paper has presented an overview of recent trends in US longwall mining. Emphasis was placed on accident and injury trends as well as data collected by a number of NIOSH researchers detailing support systems and observed ground conditions across the country.

Room-and-pillar mining is suitable for tabular bodies of room height but leaves about 40% of the rock in place while exploiting the other half. This procedure is an inefficient method of resource development but is nevertheless economically suitable for tabular seams, particularly if the seams are narrow.

OVERVIEW. A longwall change over generally takes 4 to 6 weeks. There is a need for forward planning and the use of critical path analysis is essential so as to prioritise the resources where they are needed. To prepare for a new longwall various tasks still need to be finished: The new face needs to have a level floor for the chocks to …

The function of the powered supports are to: To control strata deformation, fracture and movement around the coal face, To maintain a safe and coal producing working environment, To limit the amount of roof to floor convergence, To prevent broken rock from entering the work area, and. To secure and advance all plant on the coal face including ...

In longwall mining, a panel of coal, typically around 150 to 300 metres wide, 1000 to 3500 metres long and 2 to 5 metres thick, is totally removed by longwall shearing machinery, …

This optional feature provides users with the flexibility to operate the longwall system from anywhere within the mine's network, including the surface. Real-time remote capabilities enables faster decision making, driving eficiency and performance and enhances safety by keeping operators away from the face.

Prepared by: Ken Cram & Carol Mische, Coal Services Pty Limited – Febuary 2012

The longwall-mining method is a continuous mining system that was developed for mining coal deposits uniform in thickness and slope or where the overburden pressures may …

The term punch mining is only applied where a series of such longwall blocks is extracted, each in effect being a small underground mine. It is not used to describe the case of a large underground mine being developed by driving the mine access from a highwall or outcrop. Any method of mining could actually be used to extract coal in this way ...

Longwall mining represents a highly efficient method of coal extraction, distinguishing itself through its technique, productivity, and significant contribution to the …

This paper overviews the condition monitoring techniques and presents some examples of current longwall mining machinery applications. An expert system for condition monitoring purposes is discussed together with several case histories for underground mining machinery maintenance programs. The development of the …

Energy. Longwall mining is a form of underground coal mining where a long wall of coal is mined in a single slice (typically 1-2 m thick). The longwall "panel" (the block of coal that …

Various methods of longwall full mining with partial filling have been extensively researched to satisfy the specific mining needs of pressurized-coal and residual-coal resources. This study introduces three longwall partial-filling-mining techniques: room–pillar filling mining, parallel-strip filling mining, and vertical-strip filling …

A NIOSH review of recent trends in US longwall mining, with an emphasis on accident and injury trends, as well as support systems and ground conditions.

Longwall mining is a highly productive underground coal mining technique. Longwall mining machines consist of multiple coal shearers mounted on a series of self …

Longwalls can be operated in two ways, referred to as "advancing" or "retreating" faces or frequently simply as advance or retreat longwalls. Advancing Longwalls. Retreating Longwalls. Comparison of Advancing and Retreating Longwalls.

CHAIN PILLAR DESIGN. The diagram opposite shows a typical longwall panel with a single row of rectangular chain pillars. Chain pillars can be either square, rectangular or in some case diamond in shape. They can also be in a single or double row configuration. In Australia a single line of rectangular chain pillars is the most common.

In the method of secondary extraction known as longwall mining a relatively long mining face (typically in the range 100 to 300m but may be longer) is created by driving a roadway at right angles between two roadways that form the sides of the longwall block, with one rib of this new roadway forming the longwall face. Once the longwall face equipment has …