Fixed and Hypothesis‐Guided Soil Sampling Methods‐Principles, Strategies, and Examples

Scholz, Roland; Nothbaum, Norbert; May, Theodor W.

doi:10.1002/9783527615872.ch17

Cited by 11 publications

(6 citation statements)

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“…Edixhoven et al 2014criticize "the underreporting of Moroccan resources" (p. 502). The authors are looking for guidelines which "determine the appropriate drill hole distance" (p. 502) and refer to a "geological yardstick generally adopted in industry for measured reserves" (p. 502 , if there is certain prior knowledge and financial resources, will best fulfill the decision-makers' interests (Chilés and Delfiner, 2012;Diggle and Ribeiro, 2007;Matheron, 1963;Nothbaum et al, 1994;Scholz et al, 1994;Wellmer, 1998)? From a company's perspective, completely different drilling plans are needed for the exploration of the magnitude of the potential excavation volume of a mining area, the elaboration of a business plan (including, for instance, information used in the application of credits), and for optimiz-ing operations when the production is ongoing.…”

Section: Drilling Plans Have To Be Adjusted To Sites and Interestsmentioning

confidence: 99%

Comment on: "Recent revisions of phosphate rock reserves and resources: a critique" by Edixhoven et al. (2014) – clarifying comments and thoughts on key conceptions, conclusions and interpretation to allow for sustainable action

Scholz

Wellmer

2016

Earth Syst. Dynam.

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Abstract. Several recent papers deal with concerns about the longevity of the supply of the mineral phosphorus. The paper by Edixhoven et al. (2014), for instance, expresses doubts about whether the upward estimate of reserves by the IFDC (2006, 2010) and the USGS (2010) provides an accurate, reliable, and comparable picture, as it is based on reports that do not clearly differentiate between phosphate ore and phosphate products (i.e., marketable phosphate rock concentrate). Further, the indistinct use of the terms reserves and resources is criticized. Edixhoven et al. (2014) call for a differentiated inventory of world phosphate reserves including "guidelines which determine the appropriate drill hole distances and a detailed granularity". The claim that "humanity is on the safe side" with respect to future phosphate supply is doubted, as the validity of the IFDC's upgrading of the Moroccan data to 50 Gt phosphate is questioned. The main achievement of Edixhoven et al. (2014) is to elaborate that in the literature frequently used data on phosphate rock ore and phosphate concentrate are not properly distinguished, resulting in incorrect summary figures. In addition, it is commendable to raise the question how transparency concerning reserve and resources data and information on the geopotential of phosphate can be achieved because phosphorus is a special element. As fertilizer, it cannot be substituted and there are no unlimited resources as for the other main nutrients potassium in sea water and nitrogen in the air. However, the paper by Edixhoven et al. (2014) contains in the opinion of the authors some incorrect statements. Our comment elaborates first that several statements, such as that the upgrading of the Moroccan data is "solely based" on one scientific paper, are incorrect. Secondly, the paper comments on and illuminates a set of, in our opinion, misleading statements. These include the fact that the dynamic nature of reserves (which depend on price, technology, innovation for exploiting low-grade deposits, etc.) is acknowledged, but the right conclusions are not drawn, including the mixing of finiteness and staticness, and the way in which the critique of the USGS upgrading of the Moroccan reserves has been linked to Peak P. In particular, we clarify that reserves are primarily company data that serve mining companies for their strategic planning and may, by no means, be used as proxy data for providing global Peak P estimates. Likewise, we elaborate that drilling plans for assessing reserves have to be adjusted to site characteristics, in particular, in the case of four plateaus in Morocco and the Western Sahara comprising an area greater than 10 000 km2. We reconstruct the IFDC and USGS estimates and conclude that there is no evidence for considering the somewhat surprising increase to 50 Gt phosphate concentrate to be an unreasonable estimate for Moroccan reserves. However, the partial mixing of different units (e.g., phosphate ore and phosphate concentrate or marketable product) in the USGS data may be avoided by improving the database and using proper conversion factors. When applying these factors and assessing all reserves of marketable Gt of phosphate rock (PR-M), which is a common scale for measuring annual consumption, the magnitude of the 2014 USGS estimates of 67 Gt PR reserves does not change essentially but decreases from 64 (IFDC assessment) to 57.5 Gt PR-M (a worst-case calculation). We agree that a better harmonization of the (national) classification systems is meaningful. The discussion includes several ideas and thoughts that go beyond the paper by Edixhoven et al. (2014). We suggest that the discrepancies in the resource estimates are often caused by missing system understandings, different conceptions of sciences, and diverging world views. Finally, we suggest the establishment of a solidly funded, international standing committee that regularly analyzes global geopotential for assuring long-term supply security.

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Section: Drilling Plans Have To Be Adjusted To Sites and Interestsmentioning

confidence: 99%

Comment on: "Recent revisions of phosphate rock reserves and resources: a critique" by Edixhoven et al. (2014) – clarifying comments and thoughts on key conceptions, conclusions and interpretation to allow for sustainable action

Scholz

Wellmer

2016

Earth Syst. Dynam.

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Section: Drilling Plans Have To Be Adjusted To Sites and Interestsmentioning

confidence: 99%

Comment on: "Recent revisions of phosphate rock reserves and resources: a critique" by Edixhoven et al. (2014) – Phosphate reserves and resources: what conceptions and data do stakeholders need for sustainable action?

Scholz

Wellmer

2015

Preprint

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Abstract. Several recent papers predict a scarcity of phosphate reserves in the near future. The paper by Edixhoven et al. (2014), for instance, expresses the doubts about whether the upward estimate of reserves by the IFDC (2010) and the USGS (2010) provide an accurate, reliable, and comparable picture, as they are based on reports that do not clearly differentiate between phosphate ore and phosphate products (i.e., marketable phosphate rock concentrate). Further the indistinct use of the terms reserves and resources is criticized. Edixhoven et al. ask for a differentiated inventory of world phosphate reserves including "guidelines which determine the appropriate drill hole distances." The claim that humanity is on the safe side with respect to future phosphate is supply is doubted as the validity of the IFDC's upgrading of the Moroccan data to 50 Gt phosphate is questioned. The present paper identifies and discusses basic conceptual errors of the paper by Edixhoven et al. and related papers that predict a short or mid-term phosphorus scarcity. These include the non-acknowledgment of the dynamic nature of reserves (which depends on price, technology, and innovation for exploiting low-grade deposits, etc.), the mixing of finiteness and staticness of the ultimate recoverable resources (i.e., phosphorus that may be mined economically in the long-term future), the improper use of the Hubbert analysis (which, e.g., simply uses the USGS estimates of reserves as a substitute of an estimate of ultimate recoverable resources) and the geostatistical naive/unprofessional demand for fixed drilling plans to assess reserves. We reconstruct the IFDC and USGS estimates and conclude that there is no evidence for considering the 50 Gt phosphate concentrate as an unreasonable estimate for Moroccan reserves. However, the partial mixing of different units (e.g., phosphate ore and phosphate concentrate or marketable product) in the USGS data may be avoided by improving the data base and using proper conversion factors. When applying these factors and assess all reserves in marketable Gt of phosphate rock (PR-M), which is a common scale for measuring annual consumption, the magnitude of the USGS estimates 2014 of 67 Gt PR reserves does not change essentially yet decrease to 64 (IFDC assessment) to 58.3 Gt PR-M (worst case calculation). We argue that, a better harmonization of the (national) classification systems is meaningful. The discussion suggests that the discrepant estimates of resource estimates that can be found in literature are due to different system understandings, different conceptions of sciences, and diverging worldviews. Finally, we discuss in what way an independent and scientifically sound assessment of the phosphate resources can be realized in the long-term. We suggest the establishment of a solidly funded, international standing committee that regularly analyzes global geopotential as the source of future resources and reserves. Such a committee may be hosted by international science associations of geoscientists, given that a comparative assessment with other environmental threats reveals that investments in this field are proportional and meaningful.

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“…A major disadvantage of this sampling strategy is that soil samples may not represent the whole study site. Therefore, this sampling strategy is usually employed in relatively homogenous sites and applicable to investigations where the major objective is to determine whether heavy metal concentrations of the soils are elevated above background and/or legislative standards (Scholz et al, 1994;Petersen and Calvin, 1996).…”

Section: Soil Samplingmentioning

confidence: 99%

“…This sampling strategy allows a detailed study on each of the subgroups and increases the precision and accuracy of the estimate over the entire population. In a systematic sampling, soil samples are collected in a systematic manner, such as at a regular distance from each other across the study area, and some of the fixed sampling grids, including the bottle rack grid and the rectangular grid, are illustrated in Scholz et al (1994). The systematic sampling strategy is often employed in the geochemical mapping of heavy metals, since it enables detailed characterization of the spatial distribution of heavy metals in a large region (Appleton and Ridgeway, 1993;Xie and Cheng, 2001).…”

Section: Soil Samplingmentioning

confidence: 99%

Analysis of Heavy Metal Contaminated Soils

Wong

2003

Pract. Period. Hazard. Toxic Radioact. Waste Manage.

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Heavy metal contaminated soils can be a long-term environmental concern and potential financial liability to landowners. Hence, the assessment of heavy metal contaminated soil has received much attention in the last few decades. For a reliable and cost-efficient investigation, a well-planned sampling strategy, appropriate selection and implementation of analytical methods, and careful interpretation of results are prerequisites. This paper presents a brief overview of the preparatory, sampling and analytical stages of an investigation of heavy metal contamination of soils, particularly in the analysis of heavy metal contaminated soils.

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Fixed and Hypothesis‐Guided Soil Sampling Methods‐Principles, Strategies, and Examples

Cited by 11 publications

References 1 publication

Comment on: "Recent revisions of phosphate rock reserves and resources: a critique" by Edixhoven et al. (2014) – clarifying comments and thoughts on key conceptions, conclusions and interpretation to allow for sustainable action

Comment on: "Recent revisions of phosphate rock reserves and resources: a critique" by Edixhoven et al. (2014) – clarifying comments and thoughts on key conceptions, conclusions and interpretation to allow for sustainable action

Comment on: "Recent revisions of phosphate rock reserves and resources: a critique" by Edixhoven et al. (2014) – Phosphate reserves and resources: what conceptions and data do stakeholders need for sustainable action?

Analysis of Heavy Metal Contaminated Soils

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Fixed and Hypothesis‐Guided Soil Sampling Methods‐Principles, Strategies, and Examples

Cited by 11 publications

References 1 publication

Comment on: &quot;Recent revisions of phosphate rock reserves and resources: a critique&quot; by Edixhoven et al. (2014) – clarifying comments and thoughts on key conceptions, conclusions and interpretation to allow for sustainable action

Comment on: &quot;Recent revisions of phosphate rock reserves and resources: a critique&quot; by Edixhoven et al. (2014) – clarifying comments and thoughts on key conceptions, conclusions and interpretation to allow for sustainable action

Comment on: &quot;Recent revisions of phosphate rock reserves and resources: a critique&quot; by Edixhoven et al. (2014) – Phosphate reserves and resources: what conceptions and data do stakeholders need for sustainable action?

Analysis of Heavy Metal Contaminated Soils

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Product

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About

Comment on: "Recent revisions of phosphate rock reserves and resources: a critique" by Edixhoven et al. (2014) – clarifying comments and thoughts on key conceptions, conclusions and interpretation to allow for sustainable action

Comment on: "Recent revisions of phosphate rock reserves and resources: a critique" by Edixhoven et al. (2014) – clarifying comments and thoughts on key conceptions, conclusions and interpretation to allow for sustainable action

Comment on: "Recent revisions of phosphate rock reserves and resources: a critique" by Edixhoven et al. (2014) – Phosphate reserves and resources: what conceptions and data do stakeholders need for sustainable action?