01-08-2025
Fears massive rock column was about to collapse onto coastal walkway
A detached South Newcastle beach rock column weighing more than 1000 tonnes shifted almost a metre during heavy rain in May, prompting fears that it may collapse near the newly opened skate park and pathway.
A technical report, obtained by the Newcastle Herald via a Government Information Public Access (GIPA) application, said the 10-metre-tall column and the adjacent section of the cliff face were perched on an unstable coal seam below.
"... the column has been detached from the main cliff face for many years," the report prepared by Tetra Tech Coffey says.
"The detached column rests upon a coal seam that was observed during various phases of construction works for the Bathers Way, the skatepark and the upgrade to the rockfall catchment fence."
The cliff face, known as 'Yirannali' by the local Awabakal community, meaning 'place of falling rocks', consists of weathered sandstone and siltstone. It has numerous joints that have weathered over time.
Its stability has been the subject of concern for geologists and engineers ever since a 20-tonne rock fell 15 metres onto the Shortland Esplanade in 2002, narrowly missing a security guard.
Affectionately known as 'The Rock', the boulder sat unmoved for more than two years while civic leaders debated whether to remove it and how to stabilise the cliff.
Since then, three anchors, ranging between two and four metres in length, have been driven into the nearby rock column in an effort to stabilise it. However, they did not penetrate into the cliff face.
Ongoing monitoring has shown the column has not shifted for about 10 years.
But University of Newcastle researchers detected significant movement during May's extreme weather event.
Rainfall records show that Newcastle received the expected monthly rainfall on May 19.
"The mechanism for the detachment appears to be primarily softening of the underlying coal seam and associated weak rock, resulting in outward rotation and settlement," the report says.
"There is also a wedging effect from the boulder wedged between the cliff face and the detached block."
It was concluded that the column's movement represented an elevated risk to nearby public amenities and the Bather's Way shared pathway.
The upper promenade was closed on May 31.
Contractors subsequently removed the top section of the column and used mechanical and hand scaling to remove loose rock around the area.
"The dislodged material, or at least a portion of it, would ideally be left near the toe of the sea cliff to lend a measure of support to the base of the cliff, given that the coal seam extends southward to the point it is truncated by the fault located approximately 15 metres south," the report says.
The report noted the removal of the large boulder wedged between the cliff face and column may, in turn, destabilise the upper portion of the cliff behind the column.
An assessment was carried out in collaboration with geotechnical experts following the work, and determined that no additional works were needed in the area at this time.
City of Newcastle renewed and increased the height of the full length of the rock catch fence from the southern extent of the cliff line to the rear of the skate park amenities building in 2023-24.
It also remediated the face of the southern cliff line, with specialists scaling the cliff face to remove loose rocks before installing drainage, shotcrete and additional rock anchors, as well as soft fall to reduce rocks bouncing into the rock catch fence.
A detached South Newcastle beach rock column weighing more than 1000 tonnes shifted almost a metre during heavy rain in May, prompting fears that it may collapse near the newly opened skate park and pathway.
A technical report, obtained by the Newcastle Herald via a Government Information Public Access (GIPA) application, said the 10-metre-tall column and the adjacent section of the cliff face were perched on an unstable coal seam below.
"... the column has been detached from the main cliff face for many years," the report prepared by Tetra Tech Coffey says.
"The detached column rests upon a coal seam that was observed during various phases of construction works for the Bathers Way, the skatepark and the upgrade to the rockfall catchment fence."
The cliff face, known as 'Yirannali' by the local Awabakal community, meaning 'place of falling rocks', consists of weathered sandstone and siltstone. It has numerous joints that have weathered over time.
Its stability has been the subject of concern for geologists and engineers ever since a 20-tonne rock fell 15 metres onto the Shortland Esplanade in 2002, narrowly missing a security guard.
Affectionately known as 'The Rock', the boulder sat unmoved for more than two years while civic leaders debated whether to remove it and how to stabilise the cliff.
Since then, three anchors, ranging between two and four metres in length, have been driven into the nearby rock column in an effort to stabilise it. However, they did not penetrate into the cliff face.
Ongoing monitoring has shown the column has not shifted for about 10 years.
But University of Newcastle researchers detected significant movement during May's extreme weather event.
Rainfall records show that Newcastle received the expected monthly rainfall on May 19.
"The mechanism for the detachment appears to be primarily softening of the underlying coal seam and associated weak rock, resulting in outward rotation and settlement," the report says.
"There is also a wedging effect from the boulder wedged between the cliff face and the detached block."
It was concluded that the column's movement represented an elevated risk to nearby public amenities and the Bather's Way shared pathway.
The upper promenade was closed on May 31.
Contractors subsequently removed the top section of the column and used mechanical and hand scaling to remove loose rock around the area.
"The dislodged material, or at least a portion of it, would ideally be left near the toe of the sea cliff to lend a measure of support to the base of the cliff, given that the coal seam extends southward to the point it is truncated by the fault located approximately 15 metres south," the report says.
The report noted the removal of the large boulder wedged between the cliff face and column may, in turn, destabilise the upper portion of the cliff behind the column.
An assessment was carried out in collaboration with geotechnical experts following the work, and determined that no additional works were needed in the area at this time.
City of Newcastle renewed and increased the height of the full length of the rock catch fence from the southern extent of the cliff line to the rear of the skate park amenities building in 2023-24.
It also remediated the face of the southern cliff line, with specialists scaling the cliff face to remove loose rocks before installing drainage, shotcrete and additional rock anchors, as well as soft fall to reduce rocks bouncing into the rock catch fence.
A detached South Newcastle beach rock column weighing more than 1000 tonnes shifted almost a metre during heavy rain in May, prompting fears that it may collapse near the newly opened skate park and pathway.
A technical report, obtained by the Newcastle Herald via a Government Information Public Access (GIPA) application, said the 10-metre-tall column and the adjacent section of the cliff face were perched on an unstable coal seam below.
"... the column has been detached from the main cliff face for many years," the report prepared by Tetra Tech Coffey says.
"The detached column rests upon a coal seam that was observed during various phases of construction works for the Bathers Way, the skatepark and the upgrade to the rockfall catchment fence."
The cliff face, known as 'Yirannali' by the local Awabakal community, meaning 'place of falling rocks', consists of weathered sandstone and siltstone. It has numerous joints that have weathered over time.
Its stability has been the subject of concern for geologists and engineers ever since a 20-tonne rock fell 15 metres onto the Shortland Esplanade in 2002, narrowly missing a security guard.
Affectionately known as 'The Rock', the boulder sat unmoved for more than two years while civic leaders debated whether to remove it and how to stabilise the cliff.
Since then, three anchors, ranging between two and four metres in length, have been driven into the nearby rock column in an effort to stabilise it. However, they did not penetrate into the cliff face.
Ongoing monitoring has shown the column has not shifted for about 10 years.
But University of Newcastle researchers detected significant movement during May's extreme weather event.
Rainfall records show that Newcastle received the expected monthly rainfall on May 19.
"The mechanism for the detachment appears to be primarily softening of the underlying coal seam and associated weak rock, resulting in outward rotation and settlement," the report says.
"There is also a wedging effect from the boulder wedged between the cliff face and the detached block."
It was concluded that the column's movement represented an elevated risk to nearby public amenities and the Bather's Way shared pathway.
The upper promenade was closed on May 31.
Contractors subsequently removed the top section of the column and used mechanical and hand scaling to remove loose rock around the area.
"The dislodged material, or at least a portion of it, would ideally be left near the toe of the sea cliff to lend a measure of support to the base of the cliff, given that the coal seam extends southward to the point it is truncated by the fault located approximately 15 metres south," the report says.
The report noted the removal of the large boulder wedged between the cliff face and column may, in turn, destabilise the upper portion of the cliff behind the column.
An assessment was carried out in collaboration with geotechnical experts following the work, and determined that no additional works were needed in the area at this time.
City of Newcastle renewed and increased the height of the full length of the rock catch fence from the southern extent of the cliff line to the rear of the skate park amenities building in 2023-24.
It also remediated the face of the southern cliff line, with specialists scaling the cliff face to remove loose rocks before installing drainage, shotcrete and additional rock anchors, as well as soft fall to reduce rocks bouncing into the rock catch fence.
A detached South Newcastle beach rock column weighing more than 1000 tonnes shifted almost a metre during heavy rain in May, prompting fears that it may collapse near the newly opened skate park and pathway.
A technical report, obtained by the Newcastle Herald via a Government Information Public Access (GIPA) application, said the 10-metre-tall column and the adjacent section of the cliff face were perched on an unstable coal seam below.
"... the column has been detached from the main cliff face for many years," the report prepared by Tetra Tech Coffey says.
"The detached column rests upon a coal seam that was observed during various phases of construction works for the Bathers Way, the skatepark and the upgrade to the rockfall catchment fence."
The cliff face, known as 'Yirannali' by the local Awabakal community, meaning 'place of falling rocks', consists of weathered sandstone and siltstone. It has numerous joints that have weathered over time.
Its stability has been the subject of concern for geologists and engineers ever since a 20-tonne rock fell 15 metres onto the Shortland Esplanade in 2002, narrowly missing a security guard.
Affectionately known as 'The Rock', the boulder sat unmoved for more than two years while civic leaders debated whether to remove it and how to stabilise the cliff.
Since then, three anchors, ranging between two and four metres in length, have been driven into the nearby rock column in an effort to stabilise it. However, they did not penetrate into the cliff face.
Ongoing monitoring has shown the column has not shifted for about 10 years.
But University of Newcastle researchers detected significant movement during May's extreme weather event.
Rainfall records show that Newcastle received the expected monthly rainfall on May 19.
"The mechanism for the detachment appears to be primarily softening of the underlying coal seam and associated weak rock, resulting in outward rotation and settlement," the report says.
"There is also a wedging effect from the boulder wedged between the cliff face and the detached block."
It was concluded that the column's movement represented an elevated risk to nearby public amenities and the Bather's Way shared pathway.
The upper promenade was closed on May 31.
Contractors subsequently removed the top section of the column and used mechanical and hand scaling to remove loose rock around the area.
"The dislodged material, or at least a portion of it, would ideally be left near the toe of the sea cliff to lend a measure of support to the base of the cliff, given that the coal seam extends southward to the point it is truncated by the fault located approximately 15 metres south," the report says.
The report noted the removal of the large boulder wedged between the cliff face and column may, in turn, destabilise the upper portion of the cliff behind the column.
An assessment was carried out in collaboration with geotechnical experts following the work, and determined that no additional works were needed in the area at this time.
City of Newcastle renewed and increased the height of the full length of the rock catch fence from the southern extent of the cliff line to the rear of the skate park amenities building in 2023-24.
It also remediated the face of the southern cliff line, with specialists scaling the cliff face to remove loose rocks before installing drainage, shotcrete and additional rock anchors, as well as soft fall to reduce rocks bouncing into the rock catch fence.
