2.2 Sampling
This study’s data has been directly taken from routine quality monitoring checks made by
RNML’s environment section at the Basamuk Refinery. All samples were collected at
intervals of 40times per day or 240hourly basis and analyzed accordingly. Methods and
equipment used were approved standards that are part of the company’s routine check for
environmental quality, health and safety.
Sampling bottles were prepared with distilled water and dried prior to every daily sampling
period. Beakers and other equipment were also washed with distilled water and air dried
before being used. All the preparation was done by qualified laboratory staff following
instructions stipulated on Standard Operating Procedures (SOPs) of Ramu NiCo’s analytical
laboratory.
All the samples were collected at the mixing tank, the point of tailing discharge. Sampling
gloves were worn before all sampling proceeded to ensure quality. The samples taken from
the mixing tank were transferred to sampling bottles that pre0labeled with date, time and
location.
A total of four tailing samples were taken at 6 hour intervals for a daily (24 hour) sampling
period. For this study, the results for the 31 days of the month of August, 2013 are used. The
samples were collected using a metal sampler where a rope is attached to the handle of the
sampler and lowered into the mixing tank to fetch tailing water. Cautionary measures were
strictly observed to avoid contamination.
2.3 Laboratory Analysis
The samples were brought to the laboratory for further processing. At the laboratory, an
aliquot of the collected samples were filtered using a 0.45um diameter filter paper and the pH
measurements obtained. The pH meters were calibrated with standard buffer solution and
distilled water before the analysis of every new sample.
The discharge flow velocity was recorded from special software installed monitoring
computers. Basically, the software was designed to determine volume of discharge against
time according to the formula;
Discharge Velocity (m3
/h) = Volume (m3
)
Time (h)
The tailing content in the sampling bottles were acidified with 10020mL of concentrated
nitric acid (HNO3) to preserve and maintain solubility of dissolved metals and were analyzed
directly for heavy metals concentration using Inductively Coupled Plasma – Mass
Spectroscopy (ICP0MS) following standard instrumentation procedures. Hexavalent chromite
was analyzed using Discrete Analyzer and Mercury by Flow Injection Mercury Systems
(FIMS).
Write the main points for the above information
- Data for the study was collected from routine quality monitoring checks at the Basamuk Refinery by RNML's environment section
- Samples were collected at intervals of 40 times per day or 240 hourly basis
- Sampling equipment and methods used were approved standards for environmental quality, health, and safety
- Samples were collected at the mixing tank, the point of tailing discharge
- Samples were labeled with date, time, and location before being transferred to sampling bottles
- Four tailing samples were taken at 6-hour intervals for a daily sampling period
- Samples were filtered and pH measurements obtained in the laboratory
- Discharge flow velocity was recorded using special software
- Tailing content in sampling bottles was acidified with nitric acid to preserve and maintain solubility of dissolved metals
- Samples were analyzed for heavy metals concentration using ICP-MS, hexavalent chromite using a Discrete Analyzer, and mercury using FIMS.