Laboratory acid rock drainage (ARD) prediction tests are used to determine the most appropriate disposal options for waste rock and tailings in order to minimize environmental impact

Bureau Veritas offers the full range of ARD testing services for prediction studies and routinely conducts geochemical analysis, static testing and kinetic test programs. To better approximate site conditions, larger scale tests under specific environmental conditions can be conducted. To simulate underwater disposal of water materials, custom subaqueous disposal (SAD) tests can be conducted to predict pore water quality, seepage quality to groundwater, and surface water quality.

All test methods are offered including MEND, EPA, ASTM, and NAG methods. Custom tests include a variety of sequential leach tests. Our extensive laboratory facilities enable customized experimental design and testing over a wide range of simulated environmental conditions.

Geochemical Characterization

Bureau Veritas offers a complete suite of geochemical analyses for characterization of overburden, wasterock and tailing materials by a variety of techniques. Common analyses for acid rock drainage (ARD) prediction include sulfur speciation, carbon speciation, trace metals using various digestions and whole rock analysis. We also have the capability to tailor sulfur speciation procedures to specific ore bodies and mining projects.

Mineralogical Analysis

Bureau Veritas offers mineralogical analysis relating to acid rock drainage (ARD) using optical microscopy on polished thin sections, X-ray diffraction (XRD) and scanning electron microscope (SEM) methods.

Identification of minerals present, grain size, grain boundaries and relative abundance can be determined. The Rietveld XRD Method is also offered, allowing quantitative analysis of certain minerals at low detection limits. QEMScan bulk mineral analysis, which incorporates SEM and other methods, is also now offered.

Static Testing

Acid Base Accounting (ABA)

Bureau Veritas offers all acid base accounting (ABA) procedures including standard Sobek, modified Sobek, Net Acid Generation (NAG), and siderite corrected NP. Analyses commonly include paste pH, fizz rating, total sulfur, sulfate sulfur, sulfide sulfur and neutralisation potential (NP). We also calculate and provide maximum potential acidity (MPA), carbonate NP (NNP), net NP and NP ratio (NPR).

Static Water Leaching Procedures

Short-term water extraction (18 to 24h) procedures are routinely conducted to determine the presence of readily leachable contaminants. Methods we offer include the MEND SFE, SPLP, TCLP and Meteoric Water Mobility Procedure (MWMP). Extract analysis commonly includes pH, EC and dissolved metals by ICP-ES or ICP-MS. Other possible analytes include ORP, alkalinity, acidity, sulfate, TDS, Cl, F, Br, nitrate-N, nitrite-N, ammonia-N, TKN, total P, ortho-phosphate, CN species and other anions.

Kinetic Testing

Humidity Cell Tests — MEND and ASTM D5744 Methods

These tests are used to evaluate the long-term weathering characteristics of mine waste materials disposed under subaerial conditions. Tests are run in strict adherence to standard procedures. Possible analyses of leachates include: pH, EC, ORP, electrical conductivity, TDS, hardness, sulfate, anions (nitrate, nitrite, chloride, fluoride, phosphate, ortho-phosphate, TKN, ammonia), alkalinity, acidity, Hg by CVAF, and dissolved metal scans by ICP-ES or ICP-MS. While similar to humidity cell testing in some ways, these tests simulate site waste disposal conditions (such as saturated, non-saturated or partially saturated) more closely and at larger scale than humidity cells.

Leach Columns (Lysimeters) 

While similar to humidity cell testing in some ways, these tests simulate site waste disposal conditions (such as saturated, non-saturated or partially saturated) more closely. Water is typically added in a trickle leach fashion, but periodic flushings are possible to better simulate field conditions. Analyses that can be conducted on leachate water are the same as those for humidity cell tests.

Subaqueous Disposal Columns

These tests simulate underwater disposal of tails or wasterock and the impacts of such disposal on the water system. Clear cast acrylic type column material is used. These tests often incorporate a series of ports, which enable sampling of surface water and pore water within the waste material. These tests can be operated under anoxic conditions using nitrogen or argon to displace oxygen. A custom in-line sampling port can be installed for in-situ analysis of selected parameters such as pH, Eh, ORP and dissolved oxygen. Analyses conducted on the water samples are the same as those for leach column tests, with the addition of dissolved oxygen analysis.

Other Non-Standard Tests

Bureau Veritas has the ability to construct and operate customized test systems for the purpose of ARD and/or metal leaching prediction. This allows for investigation of scaled-up tests or custom environmental conditions to simulate field conditions. Larger scale versions of the humidity cell and static water leach tests, as well as barrel tests, are offered. These provide a larger volume of leach water, which may be required for atypical water analyses such as radionuclides investigation, confirmation of novel controls, or prevention measures. Also, customized sequential leach tests are offered.