longwall mining

LONGWALL MINING

Status in India and its application for deep

seated deposits in international scenario

CONTENTS: Longwall : Introduction LW mining equipments LW mining : Importance Status in India Analysis of the problem Present and Future

INTRODUCTION This is a form of underground coal mining

where a long wall of coal is mined in a single slice (typically 0.6–1.0 m thick).

The Longwall panel (the block of coal that is being mined) is typically 3–4 km long and 250–400 m wide.

As a cut or slice is taken along the length of the wall, the supports are collapsed, advanced closer to the face, and re-engaged, allowing roof to cave behind.

EQUIPMENTS Powered Face Supports

Shearer

Armored Face Conveyor

FEW SCENES FROM A LONGWALL MINE

LW MINING: IMPORTANCE Present ratio of production:

UG : OC = 20 : 80 The reserves suitable for OC mining are

gradually depleting. To meet the future coal demand we

need bulk production underground technologies.

The present UG mines are operating at depths of 350m and the future extraction is from deeper horizons(300-600m).

LW Mining

Higher extraction

Increased safety

Suitable for thick seams

Better for deep seated mines

Higher Quality of coal

STATUS IN INDIA

First mechanized powered support Longwall caving face:• August 1978 at Moonidih, CIL.

First Longwall face • GDK 7 Incline in September 1983 in

SCCL

Indian coal industry’s experience with LW has been somewhat mixed .

Between 1978 and 1987, nine LW packages were deployed to extract some 5.4 million tons of coal in Jharia, Raniganj, Satpura and Godavari Valley coalfields.

The experience from the first generation Longwall faces was not encouraging. Average production at Moonidih was around 750

tpd while Dhemo Main and Pathakhera gave around 550 tpd

However, SCCL achieved around 1500 tpd . The production from about twelve operating

mechanised Longwall faces in India was just 1.15 million tons in 1993-1994

utilisation factor of man and machine was within just 26%-35%.

ANALYSIS OF THE

PROBLEM

Geo-mining Conditions

Faulty Planning

Improper Selection Management of Face

Longwall Support Selection Deficiencies

Large expansion in opencast

mining

Research needs

PRESENT ACTIONS

AND FUTURE NEEDS

Planning

 Standardisation of Equipment

Spare Parts Management

Monitoring of Performance

Workshops and Overhauling Facilities

Indigenisation

Manpower Development

Thank You!