Services

John Rowland is able to act as relief Undermanager during times of absence.

John enjoys the camaraderie of this work and prides himself in his ability to get to know the physical mining conditions and the people and operational systems in place at a new site.

Whilst little time is currently available to do such work many sites choose to induct him to Undermanager level so that he can move freely around the mine whilst doing ventilation work and sometimes assist with mandatory statutory duties in the process.

Many sites recognise this is well worthwhile, especially if the intention is to use Dallas Mining’s ventilation expertise over an extended timeframe.

John Rowland has obtained the core competency “MNC.G3.A Establish the Risk Management System” and as such is well qualified to facilitate the Risk Assessment process for any situation but is more often called upon as an independent content expert to sit in on relevant risk assessments.

John's 36 years practical experience is well regarded in any forum. He is held in high regard in spontaneous combustion management having worked as a Ventilation Officer at many reactive mines around Australia for over 8 years.

The same can be said for his gas management experience having been involved in many major gas management issues at numerous gassy NSW Southern district mines.

Dallas Mining Services has had considerable experience both assembling, revising and auditing minesite management plans.

As an operational person holding statutory responsibilities in both New South Wales and Queensland, John is well equipped to practically understand the regulations and requirements in both states and has a number of resources available to assist with the risk assessment, document assembly and audit process.

John Rowland has done numerous jobs involving the planned and staged reduction and redistribution of flows during a mine closure phase. This is often over a twelve month period and the goal is to reduce mine flows and pressures to the lowest levels that the mine can be safely operated at and still exceed all statutory requirements.

As the number of men and operating units decrease then so do the ventilation demands.

Proper and rational planning during this phase can lead to very substantial savings in power and maintenance costs at a key economic phase in the lifecycle of the operation.

John Rowland at Dallas Mining Services has had considerable experience designing small auxiliary ventilation systems for underground and surface mining, industrial and environmental applications.

He has designed numerous ducting and fan installations for projects including extended single entry driveages, surface to underground long run systems, blowing auxiliary systems and the like.

Installations have been diverse and pictured is a series installation utilising 2 x 23m3/sec auxiliary fans and an evasee to drive extended distances in the absence of a primary ventilation system.

Dallas Mining has also developed a leaky duct Excel spreadsheet which involves the use of a diverse database of fan curves which can be linked to a circuit resistance under assessment and Ventsim is also utilised as a suitable modelling tool for many applications.

Considerable testing and application under real conditions has shown repeated acceptable practical results when compared to modelled values.

Most of this work can be done remotely from the site and relatively inexpensively over extremely short time frames to satisfy the client.

BELOW: An auxiliary system with a fan curve from Ventsim Visual

Dallas Mining Services has all the gear to conduct mine-wide pressure quantity surveys at the clients request.

Surveys are now done using both barometric (indirect) and the hose drag (direct) method and we have 3 x Paroscientific Barometric Standards, 600 metres of tube, electronic manometers and sufficient anemometers, electronic and mercury hygrometers, etc to carry out the job.

A full or partial Pressure/Quantity survey may be warranted if the model is grossly out of date and inaccurate and it may be cheaper and faster to start again and determine new relevant mine resistances by such an approach.

Sometimes it may be required where emergency escape conditions are critical.

Under such a scenario specific flow directions and resultant contamination in roadways may be paramount to successful safe escape strategies and Ventsim may be of assistance here.

John Rowland is currently training “Ventsim” to undergraduates and post graduate students at UNSW, UQ and WASM in Western Australia and also to students doing the National Competency MNCU1109A through Joncris Sentinel Services in central Queensland. The content is a “work in progress” and is based on John’s original 2 day course which has been around for a number of years.

The course involves:

½ day tutorial encompassing general ventilation principles and practical underground survey hints and
“Ventsim” programme overview
Student assembly of a working longwall mine model, although this can be modified for metallifereous mines as required.
Importing, exporting and merging “Ventsim” files
Adjusting fan parameters and associated model attributes
Economic analysis of ventilation changes and improvements
Auxiliary ventilation modelling and so on

Two day courses can be run for one to a maximum of 12 people at a venue suitable to the client, in any Australian state but classes of over 60 students have been taught the software in a newly developed 4 hour micro course on a number of occasions.

Personalised one on one tutoring is also available and is becoming increasingly popular as mine sites become more reliant on the use of the software in the ventilation change process. This is popular because the training revolves around the actual model the client is using so it provides a chance to check the model quality during the training process. The one on one often involves a live update of the model and tips on the correct number and placement of U/G pressure and quantity stations to speed the regular ongoing update and validity process.

VENTSIM SOFTWARE
Underground Mine Ventilation Simulation Software
Full details: www.ventsim.com

Ventsim Model Assembly

In the case where there is no ventilation model available the process is simple and straightforward.

John Rowland uses and relies on “Ventsim” software which is a world class modelling tool and by far the most popular software in use in Australia.

The client furnishes John with a plan along with quantity and pressure data from site measurements and a rough model is assembled in the Dallas office.

The accuracy of the model is then validated against measured data and John will normally spend a number of days underground picking up sufficient data to accurately validate the newly built model.

The completed model will be handed over to the client along with suggestions on how to maintain it on a regular basis.

Ventsim Model Updates

Dallas Mining specialise in updating and validating dated and inaccurate ventilation models.

Sometimes this may require dragging hoses around the pit to measure individual resistances such as overcast and L/W faces but rarely involves a full pressure/quantity survey.

The technique normally involves a couple of days underground re-establishing appropriate stations and gathering the flows and differential pressures required to get the model back into tune

When completed the client will have a functional validated and aesthetically pleasing model with which to work. The challenge then is to keep it that way and with the right tips and a bit of commitment minesite staff can keep it in a good state of tune at all times ready for any predictive work that may be necessary.

VENTSIM SOFTWARE
Underground Mine Ventilation Simulation Software
Full details: www.ventsim.com

Circuit Diagnostics leading to pressure and leakage reduction

Dallas Mining Services specialise in diagnosing the health of the ventilation circuit.

This can be done by furnishing the following:

• A copy of the mine plan in a drafting or dxf format.
• (John Rowland is a qualified mining surveyor and will show the plan
• the confidentiality and respect it deserves)A current mine ventilation model where availableA copy of the mine monthly ventilation survey data.

The above in conjunction with some relevant questioning is normally sufficient to do an initial circuit assessment by assessing the major areas of leakage and high resistance.

The work list is then defined in order of priority to examine areas of excessive leakage.

Underground inspections and relevant measurements may be used to identify or substantiate suspected areas of high resistance and leakages.

The process result is improved face air quantities and efficiencies, lowered fan pressures and operating costs and extended ventilation system life.