Mining Breakthrough: How Understanding Strata Collapse Can Save Lives and Resources

Soraya Malik in Tech & Innovation June 2025 • 4 min read.

"New research reveals the secrets of sequential overlying strata collapse in mining, offering innovative control strategies for safer, more efficient operations."

Pillarless gob-side entry retaining has emerged as a crucial technology in modern mining, significantly enhancing safety and resource efficiency. This method, widely adopted in countries like the UK and Germany, allows for longwall advance mining without the need for traditional coal pillars. In China, research and development in this area since the 1950s have yielded remarkable advancements, optimizing coal mining operations and reducing risks.

Traditional mining methods often leave behind coal pillars to support the mine roof, which can lead to stress concentrations in the surrounding strata and hinder the extraction of adjacent coal seams. Pillarless gob-side entry retaining addresses these issues by enabling continuous mining, reducing roadway drivage ratios, alleviating superseding contraction, and improving overall coal recovery. The technology has been particularly beneficial in large high-gas mines, improving both safety and productivity.

The key to successful gob-side entry retaining lies in understanding and controlling the behavior of the surrounding rock, especially the sequential collapse of overlying strata. Recent research has focused on developing effective support systems and roadside support techniques to manage the pressures and deformations that occur as the mine roof collapses. A deeper understanding of these mechanisms is crucial for ensuring the stability and safety of mining operations.

Unlocking the Secrets of Strata Collapse: What Miners Need to Know

Illustration of strata collapse in a mining operation.

Recent research has shed light on the complex process of gob-area roof rupture movement, identifying it as a critical factor in gob-side entry retaining. Through physical simulation and theoretical analysis, scientists have gained valuable insights into the characteristics of overlying strata collapse and the superposed disturbance mechanisms that affect mining operations. These findings are essential for developing effective control strategies that enhance safety and resource management.

The research reveals that as a working face advances, roof strata collapse sequentially from bottom to top, creating multiple disturbances that impact gob-side entry retaining. This process expands the scope of disturbed strata, extending from the main roof to the fracture zone. Key strata within the overlying layers control each collapse, with the main roof subsidence exhibiting three distinct stages: flexure subsidence prior to rupture, rotational subsidence during rupture, and compressive subsidence after rupture.

Flexure Subsidence: Accounts for approximately 15% of the total deformation.
Rotational Subsidence: Represents the most significant portion, contributing about 55%.
Compressive Subsidence: Makes up the remaining 30% after the rupture.

Once the master stratum collapses, the main roof subsidence approaches its maximum value, and the final span of the key stratum dictates the moment and cycling of disturbances affecting the gob-side entry retaining. The sequential collapse of overlying strata leads to fluctuations in the deformation of the gob-side entry retaining, influencing the load on the filling wall. These insights are crucial for predicting and managing the pressures and deformations that occur during mining operations.

The Future of Mining: Safer, More Efficient, and More Sustainable

By implementing a "dual-layer" proactive anchorage support system, matching roadside filling with dynamic strength, and providing auxiliary support during disturbances, mining operations can significantly enhance the stability of gob-side entry retaining. The successful application of these strategies in the Xiaoqing mine E1403 working face demonstrates their effectiveness and paves the way for safer, more efficient, and more sustainable mining practices in the future. This research provides a critical foundation for advancing mining technology and ensuring the well-being of mining personnel.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1007/s11771-018-3911-8, Alternate LINK

Title: Superposed Disturbance Mechanism Of Sequential Overlying Strata Collapse For Gob-Side Entry Retaining And Corresponding Control Strategies

Subject: Metals and Alloys

Journal: Journal of Central South University

Publisher: Springer Science and Business Media LLC

Authors: Chang-Liang Han, Nong Zhang, Zhi Ran, Rui Gao, Hou-Qiang Yang

Published: 2018-09-01

Everything You Need To Know

What is pillarless gob-side entry retaining, and how does it improve mining operations?

Pillarless gob-side entry retaining is a modern mining technique that eliminates the need for traditional coal pillars to support the mine roof during longwall advance mining. This method, widely adopted in countries like the UK and Germany, significantly enhances safety by reducing stress concentrations in the surrounding strata. It allows for continuous mining, decreases roadway drivage ratios, and improves overall coal recovery. In contrast to traditional methods, which can hinder the extraction of adjacent coal seams, pillarless gob-side entry retaining optimizes coal mining operations and reduces risks, particularly in large high-gas mines.

How does understanding strata collapse contribute to safer and more efficient mining?

Understanding strata collapse is crucial for ensuring the stability and safety of mining operations, especially in the context of pillarless gob-side entry retaining. Recent research focuses on the complex process of gob-area roof rupture movement, identifying it as a critical factor. By studying the sequential collapse of overlying strata, scientists can develop effective support systems and roadside support techniques to manage pressures and deformations. This deeper understanding allows for the implementation of control strategies that enhance safety and resource management, leading to safer, more efficient, and more sustainable mining practices.

What are the key stages of main roof subsidence during strata collapse?

The main roof subsidence during strata collapse exhibits three distinct stages: flexure subsidence, rotational subsidence, and compressive subsidence. Flexure subsidence accounts for approximately 15% of the total deformation, occurring before rupture. Rotational subsidence, representing the most significant portion, contributes about 55% during rupture. Finally, compressive subsidence makes up the remaining 30% after the rupture. These stages influence the deformation of the gob-side entry retaining and the load on the filling wall, highlighting the importance of understanding these mechanisms for effective mining operations.

How does the sequential collapse of overlying strata influence gob-side entry retaining?

The sequential collapse of overlying strata leads to fluctuations in the deformation of the gob-side entry retaining, influencing the load on the filling wall. As the working face advances, the roof strata collapse from bottom to top, creating multiple disturbances. Key strata within the overlying layers control each collapse, impacting the moment and cycling of disturbances. The final span of the key stratum dictates these disturbances, emphasizing the importance of managing these pressures and deformations to ensure the stability and safety of the mining operations, especially in the context of pillarless gob-side entry retaining.

What strategies can be used to enhance the stability of gob-side entry retaining, and what is the impact?

Implementing a "dual-layer" proactive anchorage support system, matching roadside filling with dynamic strength, and providing auxiliary support during disturbances can significantly enhance the stability of gob-side entry retaining. The successful application of these strategies, as demonstrated in the Xiaoqing mine E1403 working face, paves the way for safer, more efficient, and more sustainable mining practices. These techniques help to manage the pressures and deformations that occur during mining operations, improving overall safety and resource management. This research provides a critical foundation for advancing mining technology and ensuring the well-being of mining personnel.