ERC calculator mining – Module 12 transcript
Watch the video Mining ERC calculator training – Module 12 – Miscellaneous sheets to see examples of the investigation and contamination, general land rehabilitation and mobilisation and additional items sheets.
Welcome back to the training for the 2022 edition of the estimated rehabilitation cost calculator for mining. This is Module 12. In this module, we'll work through examples for the investigation and contamination, general land rehabilitation and mobilisation and additional items sheets.
The investigation and contamination sheet is used to cost for contaminated land investigations and treatment and disposal of contaminated material and scrap. The rolled up rates for facilities and infrastructure includes land investigation where one would be expected, example process dams, and allows for soil and scrap associated with demolition of process plants and draglines. The land investigation, contamination and scrap removal tables in this sheet are for isolated areas not associated with such facilities. The rolled up rates do not allow for any known significant contamination that may be present on the site and tables, example soil bioremediation, in this sheet can be used to account for such occurrences.
The preliminary site investigation unit rate is a one-off cost. A preliminary site investigation in the context of mine closure is typically a part of planning activities and aims to identify areas of known, suspected and reasonably probable contamination resulting from the mine operations. The preliminary site investigation comprises a review of the site setting, site history, operational history, including any accidents and incidents, hazardous liquids and solids storage schedules, and sources of potential impacts and receptors. To apply a cost for a preliminary site investigation, the user inputs the proportion of one-off cost to apply to each area, the number of investigations needed in the preliminary site investigations, together with the relevant dimensions to allow the investigation area and costs to be calculated. The proportion of one-off costs field is the multiplier on the one cost for investigation. This value is typically set to one, but there can be less if it is reasonable to assume several areas will be investigated during the same mobilisation.
An intrusive site investigation would be targeted and may not be required for all contaminated or preliminary investigation areas. The intrusive investigation rate should be applied considering risk, site history, past incidents and the planned rehabilitation program. An intrusive investigation should be considered if a site has contaminated land on the EMR or CLR, and scalping and disposal of contaminated material is not accounted for in key areas with potential for contamination, example process areas, maintenance yards, go lines. The cost of intrusive investigations is based on default rates and is calculated using the proportion of one-off cost field and the dimensions of the site. The user must add entries for both to cost an intrusive side investigation.
The entry made in the proportion of one one-off column must be made as a decimal, for example, 50% must be entered as 0.5. These entries trigger the calculation of both the land investigation one-off cost and the land investigation per unit area cost fields. The approach to estimating costs for site investigations recognises that most investigations of this nature comprise a single campaign or one mobilisation taking in multiple areas. The one-off cost allows for planning and preparation, ongoing project management, health and safety plans, work plans, and reporting. A combination of these factors must be considered in determining the number of one-off costs to apply. Examples of areas that may individually comprise one campaign are service facility areas, including fuel or chemical stores, workshops, vehicle wash downs, and sewage treatment, processing plants, including ore and product storage, mine waste storage and disposal rail loadout, and remote pit facilities like vehicle refueling, sewage treatment, secondary workshop and chemical storage. The user should enter a one for the one-off entry demonstrating the areas described in the line will be investigated in one campaign. The user can enter a fraction of one if they want to list individual areas that will be investigated in the one campaign. The by area rate accounts for activities undertaken on site.
The rate includes cost for field staff to collect soil samples, sampling equipment and consumables, and laboratory analytical costs. The user can describe the area for a land investigation by entering width and length or diameter or the area. This recognises that users will have different quantity types. Some users may use GIS that outputs area and others may measure length and width off a plan. If both length, width and diameter are added, the calculator uses length and width and ignores diameter. The calculated area column shows the calculation of area based on the user entered dimensions and if a value is entered directly to the user area column, the area for calculations column will default to that entry. The per area rate is applied only to the area to be investigated, for example a tank farm within a processing facility. In this case, only the area of the tank farm to be investigated is entered.
The next table is for removal of material from beneath the footprint of stockpiles and processing facilities that may not have been included in other input sheets. The removal of scrap and waste disposal to offsite facility tables are for miscellaneous areas not included in other input sheets. As mentioned, the rates for processing facilities and infrastructure include the removal of scrap and waste and consequently these tables are not to cover items already entered into other sheets, but for discrete, isolated items that cannot reasonably be expected to be included in the other sheets.
The management of soil contamination is not included in other sheets and the soil bioremediation table allows for the entry of specific areas whereby management of organic impacted soil is accounted for. The three different rates acknowledge that significant economies of scale will come from managing larger volumes.
The disposal to offsite facility waste levy table captures quantities from the waste register sheet if the waste levy is applicable to the site. The waste levy is now different from metro and regional zones, and the table multiplies by the rate associated with the user selection in registration. The user does not have to enter quantities to this table, but can add an optional area name description.
The General Land rehabilitation sheet accounts for activities associated with land rehabilitation that are not captured elsewhere in the calculator and can be used for buffer and fire safety areas. The default rates and user input tables in the other sheets include land rehabilitation, including footprint of facilities and access directly associated with facilities, so the general land rehabilitation sheet does not need to capture such activities for these items. For example, the default rates for waste rock dumps include grade and seed and the user input table has entries for soil amendment and long distance haul of materials if required, so the general land rehabilitation sheet is not used for these items. Rather the general land rehabilitation sheet is used for miscellaneous land areas that are not included in other input sheets. An example, maybe a rehabilitated pit that is known to require further land rehabilitation.
This sheet can be used for all areas requiring any of the following - land rehabilitation and repair of subsidence and land management, natural drainage and diversions, general grade and rip, general doze and rip, miscellaneous soil amelioration and seeding, bores, long distance carting of amendments, long distance carting of growth media, and long distance carting of clay. These tables all require a variety of user inputs to allow the areas or volumes of material to be calculated before this is multiplied by the default rates to give the total cost. Users may enter alternative rates and where this is done justification for the proposed rate must be included in the space provided at the end each table.
The long distance haul tables are for carting of materials from greater than 6 kilometres of the intended use area for items not covered by other input sheets. The distance is selected from the drop down menu which has increments extending up to 200 kilometres one way. The user enters the mass of material required and this is multiplied by the distance and the default rate to obtain the total cost for that area. The purchase price is separate to the transport cost and this is shown in the adjacent column.
The mobilisation and user input sheet allows entries for mobilisation and demobilisation, and any additional site specific items that do not have a space elsewhere in the calculator. Mobilisation and demobilisation is the process of transporting earthmoving machinery to the site for the rehabilitation work and transporting the machinery back to the supply centre. Typically, the supply centre for earthmoving equipment is a major centre such as Brisbane or Rockhampton. The mobilisation and demobilisation costs reflect the effort required for safe transport of earthmoving equipment, which typically includes floats and convoys. The calculator includes mobilisation and demobilisation rates for small, medium, large and truck and shovel fleets and in several distance ranges as shown. The default rates allow for transport both ways and therefore the user should use the one way distance from supply centre to source when determining the appropriate line to select. The default rates include costs for utility and service vehicles to support the earth moving equipment.
The number of mobilisation and demobilisation units entered is dependent on the activities selected throughout the calculator. Typically, the expectation is for only 1 entry, with the fleet size reflecting the predominant size used through the calculation. For large projects, 2 entries may be required, for example, a small fleet source from a local centre and a large fleet source from a major centre. The users who justified the distance and fleet size selected in the user notes section of the mobilisation and user sheet. Irrespective at least 1 of these rates must be applied once for every submitted ERC. This sheet requires only the input of quantities next to the appropriate line. If alternate rates are justifiable, they can be entered into the yellow cells with an explanation in the justification for alternate rate section of each line.
For small projects where the total ERC is less than $1,000,000 before mobilisation costs and multipliers, the user may choose to apply mobilisation and demobilisation costs by using the 10% flat rate option contained on the summary sheet. The user can choose this option by entering a 1 into the line titled mobilisation and demobilisation, small projects here in the summary sheet. Using this functionality will apply a mobilisation and demobilisation cost of 10% of the premobilisation and multiplies amount. If using this approach, the user should not enter quantities into the mobilisation sheet.
The additional items table allows space for the user to enter items which do not have a place elsewhere in the calculator. The cost calculated in the additional items table will contribute to the total cost and flow through to the summary sheet. All items entered into this table need to be justified in the comments space provided at the end of the table.
The user input sheet allows for users to enter free text data, which may include granular disturbance quantities and other miscellaneous supporting information. The values entered into this sheet are not linked through the workbook and the user must ensure all disturbance values are separately entered into the relevant sheets. This sheet and the associated user notes box can be used to communicate to the department where and why any disturbance areas are different between the ERC and the progressive rehabilitation and closure plan or EA.
As always, for more information or specific instructions, please consult the user guide, which is also available on the business Queensland website below the download for the calculator. And this completes the last module in the training. Thanks for joining me.
Watch the video: Module 12 – Miscellaneous sheets.