MAC: Mines and Communities

Critique of the 'Buyat Bay' CSIRO Environmental Monitoring study commissioned by PT Newmont Minahasa

Published by MAC on 2004-10-31

Critique of the 'Buyat Bay' CSIRO Environmental Monitoring study commissioned by PT Newmont Minahasa Raya (2004)

Mineral Policy Institute, Australia (

31 October 2004

1. CSIRO results indicate mine pollution at toxic levels

1.1 Toxic metals Arsenic and Antimony in Buyat Bay sediment exceed international guidelines.
Australian, US, and Canadian marine environment quality guidelines indicate thresholds where ecological impacts can be expected from heavy metal pollution in sediment. The Australia/NZ guidelines for arsenic in sediment range from 20 (low) - 70 ppm (high range). Similarly, US and Canadian guidelines identify a Probable Effects Level of 42 ppm arsenic in marine sediment. The background (natural) levels of arsenic measured by CSIRO at control sites unaffected by mine waste near Buyat Bay are at or below this level of 42 ppm.

Meanwhile, the CSIRO sampling of Buyat Bay found extremely high levels of 678 ppm, 491 ppm and 466 ppm arsenic in the area most affected by mine tailings, and the CSIRO report notes that Newmont's own monitoring has discovered levels as high as 1190 ppm arsenic. CSIRO findings show the seabed at Buyat Bay is contaminated by tailings with arsenic at ten to twenty times higher than the Australia/NZ guidelines and the US/Canadian Probable (toxic) Effects Level.

Similar results were found for Antimony in Buyat Bay sediment, another toxic heavy metal contained in Newmont's mine tailings. The CSIRO found Antimony at 255 ppm, 208 ppm and 188 ppm in the tailings-affected area in Buyat Bay, compared with natural levels at nearby control sites of 20 ppm. CSIRO mentions that Newmont has found levels as high as 1330 ppm and 1160 ppm Antimony. CSIRO findings show that the seabed of Buyat Bay is contaminated by Antimony in Newmont's tailings, at a level which exceeds guidelines from US/Canada (9 ppm) and Australia/NZ (25 ppm) by approximately ten times.

1.2 Toxic metals in tailings are being released to the environment.
CSIRO collected water samples and compared the levels of toxic metals at several depths above the Buyat Bay sea floor. For example, at Buyat Bay sample site B, the CSIRO found that arsenic in seawater 9 meters above the bottom is two-and-a-half times higher than concentrations at a depth 14 meters higher, and Mercury in seawater 9 meters above the bottom is more than 10 times higher than concentrations at a depth 14 meters higher.

There is a striking correlation - the closer samples are taken to the tailings on the sea floor, the higher the level of toxic metals such as arsenic. This is an important finding because Newmont has asserted that the heavy metals in the tailings are not significantly soluble and do not act as a source of metals contamination. CSIRO's data indicates that the millions of tons of Newmont's mine tailings in Buyat Bay are in fact continuously releasing metals into Buyat Bay, a situation which is acknowledged in the first paragraph, page 20 of the CSIRO report.

2. CSIRO study seriously flawed.

The CSIRO laboratory processes are state-of-the-art, indeed much of the document is taken up with description of the sampling methods and analytical procedures. However, the same thoroughness and attention to accuracy was unfortunately not exercised with sampling design, and with the discussion and all-important conclusions and executive summary.

2.1 Inadequacies in the CSIRO study.
· The half-page introduction is no adequate background explanation of the ore body, mining, gold extraction and waste processing. The CSIRO report actually begins with the misleading statement that "mining ceased in October 2001". Excavation ended on that date, but what most people regard as mining activity, i.e. the processing of ore and disposal of mine wastes continued three more years until end of August 2004.

· There is no quantification of the rate of tailings disposal (over 2,000 tons / day) nor of the total volume of waste disposed of into Buyat Bay (in the millions of cubic meters). These factors which dictate the total supply and future fate of heavy metals in tailings in Buyat Bay have crucial importance for proper sampling design. Contamination of the food web by heavy metals such as arsenic is a gradual and steadily ongoing process, as long as the heavy metal contaminated sediment remains in Buyat Bay. The report does not adequately consider the quantity and future fate of the heavy metals in sediment over the coming years.

· There is no clear basis for selecting a limited range of contaminants to analyse. The CSIRO only considered 5 metals, plus arsenic and cyanide. Ideally the selection of substances for analysis should be based on the composition of the ore body, and chemical reagents used in tailings. In the absence of such information, it would be appropriate to include cadmium, chromium, lead, nickel and zinc.

· There is no discussion of the pressing issues in the report apart from a mention of 'community concerns about contamination of coastal waters'. The study designer needs to ask: what are the community concerns - health, water pollution, decline in fishery, fish kills or diseases, etc? It is usual to identify these concerns in order to provide a basis for the sampling design.

· The sampling did not examine a representative range of marine life. The sampling design should take account of the ecology of the species involved (especially the likelihood of long term residence in Buyat Bay, feeding behaviour and food items), consumption rates and other factors. Appropriate target species should be resident in Buyat Bay rather than passing through. The location where the fish were caught also should be documented, and better still controlled so that they definitely come from the impact area. Quite a few of the fish were bought in the local markets which provides no certainty that the fish came from the bay. Many marine species of key ecological importance were not sampled, such as ecologically crucial plankton, and non-fish marine food species such as filter-feeding mussels, prawns, crabs and so on. The key "not polluted" conclusion on page 43 therefore is not proven.

· The fish, sediment and water samples collected over such a limited period of time, only 2 days, do not allow for seasonal and weather variability both on land (fluctuation in river flows and groundwater) and at sea (currents, tides, wave action) which affect such phenomena as sediment transport, disturbance, and dissolved metals levels in groundwater. Such limited sampling is inadequate to draw general conclusions.

· The study uses only a few seawater sampling locations in Buyat Bay and the sampling at each site occurred over a limited time. As a result the design does not adequately allow for variability. For example, in the tailings disposal area there are only 3 samples from the top, middle and bottom of the water column at 3 sites (9 in total) all of which were collected over a few hours. Multiple samples should have been collected at each depth, at regular intervals over a reasonable period, and at a number of sites. The CSIRO samples are insufficient for general conclusions to be drawn from the results.

· Similarly, the number of sediment samples at each location is low: 3 for the tailings area, and only 1 at each of the rivers , the lake and the reference sites. No allowance for spatial variation. This may be why much higher levels of arsenic, mercury, antimony and zinc were recorded in the PT NMR studies - there were insufficient samples in the CSIRO study to account for the variation.

2.2 Inadequate and misleading discussion and conclusions
Language used in the executive summary glosses over negative findings. Executive Summary point 5 reads: "significant enrichment of arsenic and antimony in the area affected by tailings deposition in Buyat Bay". This is misleadingly innocuous language which fails to mention the order of magnitude of metal pollution above international guidelines.

The CSIRO study is not truly "independent". The existence of the CSIRO study first came to public attention following a report about pollution in Buyat Bay published in the New York Times. Newmont referred to the CSIRO testing in a media release the following day entitled "Newmont Responds to New York Times" (Sept 8, 2004). The following day, non-government organisations contacted the CSIRO and requested a copy of the report. One week later, the CSIRO explained that the report was not yet completed, and that Newmont had quoted partial results relating to seawater samples only. The CSIRO further indicated that the scope and results of the CSIRO study could only be released with the permission of Newmont's lawyers. The report was finally officially sent to a US non-government organisation by Newmont on the 28th of October 2004.

The senior principal research scientist involved in the CSIRO study also has a history as a consultant to the Porgera gold mine in Papua New Guinea, which together with the Ok Tedi mine, is one of only a handful of mines in the world which practices the destructive practise of disposing of mine waste directly into a river system. Newmont's quoting of results prior to report completion, the lack of transparency by researchers, and the fee-for-consultancy relationship between CSIRO researchers and mining companies disposing of mine waste directly into rivers and oceans means the report can be seen as far from "independent".

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