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Kerusha Naidoo is currently employed under the Ambient Division at Skyside South Africa – initially as a Specialist in Ambient Reporting (Project Manager) and more recently as a Business Development Manager. Kerusha acts a Technical Signatory for Skyside, appointed by SANAS in 2016.

Skyside is pleased to announce that a paper prepared by Kerusha Naidoo and our Director, Prof Harold Annegarn won Best Scientific Paper at the 2020 NACA Conference, making it two in a row for Skyside.  We value the recognition for work that goes beyond our commercial engagements.  Skyside values Innovation and we aim to be “proactively engaged in our profession community”.  This paper and award symbolise our Values.

Said Kerusha: “One is never too old to learn, and remember, knowledge is power! Being a co-author with Professor Annegarn has been and continues to be a rewarding experience, along with my manager, Ruth Wandera for the past 5 years.”

In 2019, Kerusha and Harold undertook a validation study on the Seasonal Patterns and Long-term Trends of Dustfall around Gold Mine Tailings Storage Facilities (TSF) on the East Witwatersrand in South Africa.


Long-Term Monitoring Makes a Difference

They summarised the work in a paper which reported a time series analysis of a 20-year (2000-2019) monthly dustfall record in proximity to legacy TSFs excavated as feed material and the ERGO mega-deposition TSF south of Springs, East Witwatersrand.

The ARIMA[1] time series analysis was applied to decouple seasonal variations, long term trends and residuals. An outcome of the study was that strong seasonal patterns were observed at sites close to operational TSFs, driven by combined factors of exposed surfaces, above average wind speeds and rainfall.

The study uncovered trends that are attributable to the extent of mitigation measures – water or chemical binder spraying (dust suppression) on excavated TSFs; windbreak fences and prompt vegetation on the ERGO deposition TSF.

A brief historical timeline of the Witwatersrand TSF was reviewed from the 1960s through to 1985, along with the use of historical satellite imagery available on the Google Earth platform dating back to 1984.  The analysis confirmed that dustfall monitoring is a robust indicator for management and regulatory purposes of localised environmental dustfall, as well as the value of consistent long-term dustfall monitoring using a standardised methodology.

In this contribution, Skyside investigated a 20-year record of monthly dustfall surrounding TSFs in Brakpan and Springs, including the Brakpan mega-TSF, located ~13 south of Boksburg and Brakpan, Gauteng.

[1] ARIMA, short for ‘Auto Regressive Integrated Moving Average’ is actually a class of models that ‘explains’ a given time series based on its own past values, that is, its own lags and the lagged forecast errors, so that equation can be used to forecast future values.

Dustfall Monitoring Adds Value

Arguments were presented that the trend component is indicative of the combination of source extent and mitigation effectiveness. These factors are within the control of the operator, and thus indicators of the success or otherwise of dust management strategies on the part of the operator. In contrast, the seasonal and irregular components are driven by external factors (meteorology and random variability, respectively). The extracted trend values for the Brakpan TSF dustfall sites are explained in terms of significant changes in the operations and dust control regimes on the facility.

The results overall demonstrate the value of dustfall monitoring as a valid environmental indicator for managing both short-term and long-term trends of fugitive dust sources.

Kerusha was presented with the Award for Best Scientific Paper at the 2020 NACA Conference.

Kerusha hopes to be an inspiration to her colleagues and believes that experiences like this one can then be infiltrated into the workspace and streamlined to fellow colleagues as it is a learning curve for us all.