Frequently Asked Questions
- Where are the mining activities taking place?
- You are mining under the town of Bendigo, is there any risk of ground caving or collapse?
- What happens to all the water from the old underground workings?
- How do the miners get air down the decline?
- Is Bendigo Mining a signatory to the Australian Minerals Industry Framework for Sustainable Development Enduring Value?
- What are Bendigo Mining's plans for rehabilitation?
- What is done to minimise impacts on the environment of the surrounding area and on residents’ amenity?
- How is the impact of the operation known?
- Will the decline go into the old workings?
- What type of equipment is used?
- How many people work at the Mine?
- How much gold did Bendigo produce?
1. Where are the mining activities taking place?
The focus of our current operations is at the Kangaroo Flat Mine, a 59-hectare site bounded by Ham Street, Diamond Hill Rd, Golden Gully Rd and Adelaide Gully Rd in Kangaroo Flat, 6 km south-west of Bendigo.
We also have operations at: New Moon in Eaglehawk where our water treatment plant is situated, a future mine site at the historic Williams United Mine in Eaglehawk, ventilation shafts at Adam Street and Eve Street in Quarry Hill, and Woodvale where our evaporation pond facility is located.
The Swan Decline portal (underground mine entrance) and Bendigo Mining's main office are located at the Kangaroo Flat Mine. This site includes storage areas for by-product rock (rock containing little or no gold), offices and workshops, the gold processing plant and a 30-metre deep box cut which provides access to the decline. A feature of the site is an earth wall (called a bund wall) which borders the operational area and assists with noise attenuation. The wall has been revegetated. During the development phase of the decline, the rock was hauled to the surface in trucks and placed in heaps on the site. Rock piles were then shaped, covered with sub-soil and top soil and progressively revegetated, and this will continue as the mine expands its operational areas. During the production phase, when ore is removed from the mine, much of the rock from underground will be used to fill the voids left from ore removal. The decline was initially dug with a boring machine known as a roadheader (similar to the one used to make the City Link Tunnel in Melbourne) but now the rock is broken by drilling and blasting. Ground vibration and air vibration are strictly controlled to ensure the protection of buildings and to minimise impacts on the environment. Now that the decline is some 1000 m vertically below surface, ground vibration is barely detectable at the surface and the impacts of our blasting go almost unnoticed.
You are mining under the town of Bendigo, is there any risk of ground caving or collapse?
The Company is extracting ore from beneath the historic workings at depths of greater than 1000 m. The old workings, consisting of some large underground openings, are mostly open and stable. Large-scale collapse into our mined-out voids is not possible due to the relatively small openings that are created relative to the depth of extraction below the City and the fact that most of the voids are back-filled with waste rock.
However, the existing feature of collapsing historic shaft collars and other old near surface workings is likely to be an ongoing occurrence. These small collapses due to failed shaft cappings or near surface pillars are unrelated to our activities; they occurred before we started mining, have continued since we commenced mining and can be expected to continue into the future, particularly after significant rainfall events.
What happens to all the water from the old underground workings?
Water extracted from the old and new underground workings is pumped to the surface at a number of sites and is transported by pipeline to an existing shaft on the Londonderry Reserve, in Myrtle Street. Water flows down this shaft through the historic workings to a point to the north of Eaglehawk, where it is extracted and pumped to our evaporation ponds at Woodvale.
How do the miners get air down the decline?
Large fans, located underground, force air up a shaft in the area known as Quartz Hill, bounded by Thistle, Adam and Sullivan Streets. In turn, this causes air to be drawn down the decline and the intake shaft at Eve Street in Quarry Hill and it is directed to the working face by ventilation ducts. Additional shafts will be constructed as the mine expands.
Is Bendigo Mining a signatory to the Australian Minerals Industry Framework for Sustainable Development Enduring Value?
Yes. Bendigo Mining is a signatory to Enduring Value and has been working hard to implement the principles of Enduring Value.
What are Bendigo Mining's plans for rehabilitation?
As part of the early planning and permitting process for the project, Bendigo Mining commissioned local company Goldfields Revegetation to devise and implement a comprehensive plan for the progressive rehabilitation of all work sites.
This progressive rehabilitation program includes clearing only as required, and revegetating disturbed areas as soon as possible. Progressive rehabilitation makes good economic and environmental sense, as it ensures the final landforms are revegetated sooner rather than later thus keeping the environment disturbance to an absolute minimum.
Goldfields Revegetation is using innovative methods to ensure as many indigenous species as possible are returned to the site. Seeds from over 70 indigenous species were collected prior to earth works on the site. To date, more than 80 species had been established on the mine site.
What is done to minimise impacts on the environment of the surrounding area and on residents’ amenity?
Bendigo Mining values the environment and community in which we operate and impact minimisation efforts include the following:
- Construction of an earth wall around the site for noise and visual attenuation.
- Use of equipment modified to minimise noise emissions.
- Utilisation of an extensive sprinkler system for dust suppression.
- Design of blasts to ensure vibration levels remain below prescribed limits.
- Extensive program to provide information to neighbours.
- Rapid response system for complaints and inquiries.
- A comprehensive monitoring program.
Company activities are governed by strict operational limits set by government, and if a non-compliance is identified, the activity is immediately investigated.
Bendigo Mining is continually working to identify practices that minimize impacts on neighbouring residences and has a 24-hour free call hotline (1800 640 959) for residents who may be disturbed by the mine's activities.
How is the impact of the operation known?
The environmental monitoring program, conducted under the direction of independent organisations, includes the following:
- Measurements of noise levels at adjacent residences.
- Measurements of respirable dust concentrations in the air at adjacent residences.
- Measurement of ground vibration resulting from blasting.
- Routine sampling and analysis of surface, ground and drinking water.
- Measurement of energy efficiency.
- Quarterly vegetation surveys.
- Surveys of community attitudes and perceptions to assess social impact.
The results of this monitoring are reported to the relevant authorities and to an Environmental Review Committee that includes government, regulatory and community representatives.
An environmental report is published annually and is available on this website.
Will the decline go into the old workings?
The areas targeted by the Company are below the historic workings from depths of 750 m to 1500 m.
To reach this point, the decline passes through a number of lines of reef and in some cases is in close proximity to old workings - but these do not pose a problem for development of the decline as they have been well researched to pinpoint their exact location.
The Bendigo Mining geology team has 'reconstructed' large parts of the historic Bendigo goldfield to create a 3D computer supermodel of what lies beneath our feet. So far, we have invested the equivalent of 40 person-years of work into 'shaft rebuilding' to create this extraordinarily detailed map of subterranean Bendigo.
Why? The research is vital for several reasons - but most importantly, to protect our underground workers from a sudden inrush of water which could pose a major safety hazard.
The thousands of kilometers of shafts, drives and tunnels beneath Bendigo now hold what historian James Lerk terms 'a vast reservoir' – and one of the challenges of the Bendigo Mining project has been how to deal with that reservoir to mine safely and efficiently at depth.
Of the 5,000-plus shafts on the Bendigo field, the team has so far 'rebuilt' around 290 historic shafts and their associated drives and tunnels, some plunging over a kilometre deep. Using old newspaper stories, mine managers' reports and government geological survey records spanning more than a century of mining in the region, we have gradually built up a comprehensive picture of the old underground workings.
We then assign each piece of the 3D jigsaw a 'degree of confidence' about its accuracy. For some confidence ratings, new work can go within tens of metres of the expected location of the old work. For others, the new work won't go within 100 metres because of a lack of certainty in the records and the overriding need to guarantee worker safety.
The decline path crosses the following lines of reef and associated old workings:
- Carshalton
- Napoleon
- Nell Gwynne
- New Chum
- Sheepshead
- Deborah
What type of equipment is used underground?
All the equipment used underground is diesel or electric-powered.
- Bogger: This is an underground front-end loader, especially designed for loading and hauling underground. These machines carry up to 17 tonnes each load and weigh as much as 48 tonnes when empty.
- Trucks: The underground dump trucks carry 30-50 tonnes per load. They are specially designed 4-wheel-drives with articulated steering. Trucks have been fitted with customised noise attenuation features to minimise noise emissions.
- Jumbo: This is a mobile machine capable of drilling horizontal or vertical holes into fresh rock.
- Utes: These are emission tested for underground use.
How many people work at the Mine?
There are about 120 people working at the Kangaroo Flat Mine.
Our workforce comes mainly from the local community and the company has a commitment to local employment where possible.
How much gold did Bendigo produce?
More than half the reef gold in Victoria has come from the Bendigo region. In Australia, Bendigo is still the second largest goldfield, after Kalgoorlie's Golden Mile, when measured in total gold production, and among the top ten world wide.
