AMC HP SRU™ limits environmental impact in the Flinders Ranges

AMC HP SRU™ limits environmental impacts in the Flinders Ranges

AMC HP SRU™ limits environmental impacts in the Flinders Ranges

Accessibility and environmental impact presented an expensive challenge for the customer’s exploration drilling project, remotely located in South Australia’s Flinders Ranges. AMC’s HP-SRU™ was trialled to minimise site footprint and reduce operational costs at the steep and densely vegetated site.

AMC HP-SRU™ achieved:

  • $9,100* Total savings per hole/rig (8 day trial period)
  • up to $4,000 savings in mud waste disposal
  • $2,500 savings from reduced environmental costs
  • $1,800 savings from increased operational efficiencies
  • 79% reduction in mud usage
  • 60% reduction in water usage
  • 70% reduction in drilling footprint
  • 20 minutes set up time
* Rental is not included as rates may vary depending on the terms of the contract.

Trial Overview

Date May 2014
Location South eastern edge of the Flinders Ranges, South Australia.
Drill hole information A PDC drill bit was used to 100m, then HQ to the target depth of 450m
Cuttings Management Captured from HP-SRU™ chute in bulk bags and heli-lifted from site
Mud information CR-650, foam and lubricant – mixed in the HP-SRU™ ’s mixing tanks
Water Good quality potable water was pumped from a water truck 3km uphill via poly-pipe. It was then stored in a 10,000L tank next to the drill rig.
Geology Variable black shale and conglomerate.
Access / Drill Pads Limited access – inaccessible by road. Minimal drilling footprint, approximately 15 x 6 meters surrounded by vegetation
Activity Exploration drilling – one rig.

Background

The customer’s diamond drilling operation remotely located in the Flinders Ranges, South Australia. The site was not accessible by road and only a small footprint for drilling was available due to the steep hills and dense vegetation. All operational equipment needed to be air lifted to site, an expensive logistical challenge for the drilling company.

Lift, Swing and Placement – Ready for Operation in 20 Minutes

AMC’s HP-SRU™ is very light, highly mobile and was installed for operation with only four heli-lifts. Each piece of the unit has been designed to fit quickly and easily together – no aligning of nuts and bolts is required. Following delivery at the trial site, the unit was operational within 20 minutes. The four components of the HP-SRU™, each weighing less than 700kg each, fitted together easily on the base frame. Colour coded hoses and assemby guides also ensured the unit was easily assembled.

Compact Site Set Up – Footprint Reduced By 70%

When using the HP-SRU™ the site set up includes the unit, drill rig and a water storage tank for water supply. A traditional set up requires at least three low rise mud settling tanks, the drill rig and a water storage tank. During the trial the footprint of then HP-SRU™ was 8.7 m2 (including workspace), compared to a footprint for traditional mud settling tanks of 31 m2 (including workspace).

Sumpless Technology Efficiently Removed Cuttings

The HP-SRU™ removes cuttings via the centrifuge. The drier sludge (~65 - 70% dry) is then collected in bulk bags directly from the unit’s chute for removal – no double handling is required. In contrast, the traditional set up includes three low rise settling tanks. Once the tanks are saturated with cuttings, the cuttings are shovelled into bulk bags and heli-lifted for disposal.

The volume of the cuttings from the settling tanks is larger; as they contain more water than cuttings from the centrifuge, resulting in additional and costly heli-lifts for disposal (heli-lifting is approximately $2,000 per hour).

Consistent and Optimal Mud Properties

Maintaining adequate mud viscosity is essential for completing a hole successfully. Steep terrain, uneven tanks and limited power supply enhance the challenges of effectively mixing mud on site. The HP-SRU™’s mixing tank, hopper and agitator overcome these challenges making it easier and more efficient to mix mud and maintain optimal viscosity. During the trial the unit demonstrated its ability to remove cuttings, keep a consistent viscosity and reduce the mud weight or specific gravity (SG). The table below sets out the properties of the mud taken from the collar and after it had been processed by the centrifuge (centrate).

Mud Properties

Viscosity of water (sec/quart) 26 SG of water 1.00
Viscosity of mud (sec/quart) from collar 35 SG from collar 1.04
Viscosity of mud (sec/quart) from HP-SRU™ centrate 35 SG from centrate 1.02

Significantly Lower Cost of Sludge Disposal

During the trial, the mud was mixed inside the HP-SRU™ using the agitator and hopper, then pumped downhole and returned and cleaned via the centrifuge. Waste had to be transported from site by helicopter, with each lift carrying a maximum of 700kg. Once reaching the end of hole, 900L of left-over volume of mud needed to be disposed of, which would require two heli-lifts. Without the HP-SRU™, approximately 7,000L of left over mud. This quantity of mud waste would require ten heli-lifts.

Mud Costs 79% Lower Per Day

The HP-SRU™ and the traditional site set up both enable mud to be recycled via a turbo pump from the collar returning to the SRU™ or settling tanks. The mud is then processed by the centrifuge or settling method before being reused down hole. During the HP-SRU™ trial mud costs per day were approximately $25.80. Without the unit mud costs were estimated to be $121.25 per day a saving of over $750 during the 8 day trial period.

Water Usage Reduced by 60%

During the trial water usage was important as it had to be pumped up hill and stored. When using the HP-SRU™ the drill rig used approximately 2800L of water per day comprising 950L within the unit’s tank, plus additional water needed for losses down hole. Without the HP-SRU™ three tanks plus additional water for losses would be required, totalling approximately 9000L per day.

Environmental Benefits

Using the Heli-portable SRU™ helped benefit the environment by reducing the drilling footprint, saving water, reducing the volume of waste cuttings and disposal and eliminating the risk of contamination to the immediate environment in the Flinders Ranges.

Operational Efficiency (KPI's)

During the trial optimal mud conditions and a cleaner drill bit reduced the number of rod trips. The unit has also demonstrated a reduction in stuck pipes, corrosion on the swivel and bean pump, together with savings on rig downtime, improving productivity.

$9,100 Total Savings per Hole/Rig (8 Day Trial Period)

The HP-SRU™ delivered significant savings across a number of different areas as outlined below.

ESTIMATED SAVINGS (BASED ON 8 DAYS TO REACH TD) SAVINGS PER HOLE / RIG
Water usage 60% reduction
Mud usage $800
KPI and meters drilled – rod trips, maintenance and reparations $1,800
Environmental – site rehabilitation $2,500
Disposal of waste mud – additional heli-lifts $4,000
Approximate savings per hole /rig* $9,100

*Does not include rental of the HP-SRU™ as the terms of the contact vary depending on the project.

Project Outcome

AMC’s HP-SRU™ was developed to enable customers operations to continue at remote or inaccessible locations. The unit also enables exploration projects to be carried out on a minimal drilling footprint and reduces environmental impact.

Feedback from the trial confirms the drillers, geologist and helicopter pilot were impressed with the unit – particularly its four-part design, which fits easily together without having to align nuts and bolts.

The geologist on site indicated that he would use the HP-SRU™ again as it was easy to use, resulted in less spillage and overflows, produced drier cuttings and the drillers enjoyed using the unit.

“Everyone was impressed with the SRU™, including the Mines Department who did an inspection the week before drilling finished. I would certainly use the SRU™ for any further helicopter supported drilling programme.”

The trial demonstrated a significant reduction in the environmental footprint including water usage, clearing of vegetation and digging of earth sumps.

For more details on this successful project, contact amc@imdexlimited.com

Key Benefits for Drilling Company
  • Quick and easy installation, ready for operation in 20 minutes
  • Reduced water consumption
  • Reduced mud usage and associated costs
  • Reduced slurry volume, waste cartage and disposal and associated costs
  • Increased KPIs and metres drilled
  • Reduced wear and tear on drill components
  • Improved bit on bottom time
  • Less rod trips, pulling and reaming
  • Ability to effectively mix mud on site
  • Improved on-site health and safety, reducing slips and hazards due to mess, mud and water.
Key Benefits for Resource Company
  • Lower overall project costs
  • Minimises impact on the environment
  • Easier access to site / smaller site footprint – improves relationships with landowners
  • Lower costs associated with managing sump / site rehabilitation
  • Reduced water wastage – depending on the amount of mud left after TD potential savings on heli-lifts for disposal.
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