GRT7000 Polymer Seal Road Dust Monitoring

Background

About the client

Our client was a global gas company that is a leading natural gas producer, focused on developing Queensland’s world-class onshore gas reserves. The road dust monitoring was performed on a section of road, south of Glen Mona Road junction and under the jurisdiction of the Queensland Western Downs Council. The road was used by both light and heavy vehicles involved in Coal Seam Gas (CSG) projects with the frequency of the heavy vehicles approximately 60 per day. Light vehicle traffic was also due to the grazing and farming activities occurring at the properties adjoining the road. The soil was sandy loam in nature, although no prior soil analysis was performed to ascertain if any imported materials were used for the road construction. Dust suppression is a necessary good for most fit-for-purpose unsealed roads in Australia and the benefits of managing dust using polymer technologies is highlighted in this 5-day road dust monitoring case study. 

Efficacy of dust suppression was evaluated using the following techniques:

• Dust monitoring comparisons between GRT treated and untreated sites, with consideration of background dust levels at Kerrs Road, Kogan. 
• Analysis of dust deposition samples for insoluble solids, ash, and combustible matter composition for the different sites. 
• Evaluation of total suspended solids (TSP) concentrations. 
• Statistical analysis and interpretation of results. 

Dust Monitoring Methodology

The road was first treated with GRT7000 in August 2013. Coating occurred at 10-week intervals and the last application and maintenance was completed on 26th February 2015. The objective of dust monitoring was to provide evaluation of the performance of GRT7000 in suppressing dust from a section of treated road compared to an equivalent section of untreated road.

The evaluation was based on the statistical comparison of dust field measurements for the treated and untreated sections of the road. Additionally, a background location was used as reference point. 

The dust monitoring project was scheduled over 5 days to avoid sampling during or immediately after a significant rainfall with the objective of collecting data during normal to worst-case scenario of the dustiest conditions. These were the test methods used in the sampling methodology:  

Sampling site selection and setup: AS/NZS 3358.1.2007 Methods for sampling and analysis of ambient air – Guide to sitting air monitoring equipment. 

Dust deposition: Simtars Procedure LP0182 – Procedure for Determination of Dust Deposition (AS3580.10.1).

Dust monitoring: AS/NZS 3580.9.9:2006 Methods for sampling of ambient air. Method 9.9: Determination of suspended particulate matter – PM10 low volume sampler – gravimetric method. 

The general sampling area for the project was selected by GRT near Kogan due to operational requirements. The project required three representative sampling sites:

• Site 1 – treated section (20 metres)
• Site 2 – untreated section (20 metres)
• Site 3 – background location (20 metres)

The road orientation was north-south. Sites 1 and 2 were located on the western side of the roadway whereas site 3 was located on the eastern side of the roadway. Specific requirements had to be considered for sampling of the sites:

• Select road segments with similar traffic loads.
• Not near road junctions or bends.
• Similar soil types.
• Open area, not encumbered by excessive vegetation. 
• No nearby soil disturbance or activities.
• Sufficient separation between treated and untreated areas.
• Similar orientation to prevailing winds expected to have some easterly component.
• Safety aspects with regards to avoiding obstruction of road, safe access and vehicle parking. 

Three Deposition Gauges were used at each of the three monitoring sites. Two Microvol samplers were used at sites 1 and 2, and a single sampler at site 3. The setup included replicates which measure the variability of the sampling systems and consequently allow statistical analysis of the data to be performed. 

What is GRT7000?

GRT7000 is a unique product and process developed in Australia by GRT, termed “Polymer Sealing”. GRT7000 is a specially formulated clear drying polymer emulsion added to watering trucks and diluted with water to make the required percent solution. It has been formulated to minimise fugitive dust on unsealed roads by creating a tough and waterproof surface.

GRT7000 is designed specifically for the conditions of the construction, forest, oil, and gas projects, mine sites and other haulage roads and can be applied using existing site water trucks, tankers, or sprinklers. GRT7000 binds the silty dust particles together preventing them from becoming airborne. 

Importantly, subsequent maintenance applications with GRT7000 will result in a build-up and after a period, due to the accumulative residual of product, the application of GRT7000 can be suspended or reduced until blow on, tracked on, or traffic generated dust warrants another application of product. The use of GRT7000 helps maintain the surface integrity, by keeping the fines that bind unsealed roads on the surface.

GRT is dedicated in developing sustainable, environmentally friendly products, GRT 7000 is safe, non-toxic, has a low carbon footprint and is biodegradable meeting the strict environmental criteria imposed by the local council.

Qualitative Benefits

The GRT7000 treated roads not only became dust-free but complications between the farmers were also reduced. The GRT7000 polymer sealant works differently to the standard market sealants. With each application, an accumulating number of silty dust particles are bound together, preventing them from being airborne. In this dust monitoring project, the benefits and results gained were clear: 

5 KEY QUALITATIVE BENEFITS OF USING GRT7000: 

1. Elimination of dust and its impacts (visibility, health, surrounding areas). 
2. The stable, waterproof sealed surface.
3. Road corrugation and potholing prevention.
4. Improves skid resistance and rolling resistance.
5. Environmentally friendly product. 

Dust Monitoring Findings 

• The insoluble solids dust deposition results showed that the treated site had notably lower deposition than the untreated site.
• The untreated site’s mean for insoluble solids was more than seven times that of the treated site.
• A result for the untreated site mean was 14 times higher than the treated site. The untreated site had the highest proportion of ash solids relative to combustible solids. Ash solids are indicative of mineral matter which is the expected content of the dust from the untreated road surface.
• The treated site had the highest proportion of combustible solids which reflects the lower entrainment of road dust at the treated site and greater influence of organic material from the surrounding trees and grasses.
• The other dust monitoring technique, for Total Suspended Particulates, showed a similar relationship between measurements at the treated compared to untreated site: the TSP mean for the untreated site was four times that of the treated site.
• The dust results at the treated site were actually lower than those at the control site away from the road in the farmers paddock!

The results showed, statistically, that at Kerrs Road during the period 16th – 21st March 2015 the applied GRT7000 product was effective at supressing dust, so much so that results at the road, were better than in surrounding, rural landscape. It decreased the mean insoluble fraction of deposited dust by 7 times and the TSP by 4 times.