Feedstock characterization

Project Developers shall submit a Feedstock Characterization Report for each spreading event, that includes the applicable information outlined in the following sections: a qualitative description of feedstock, measurement results, CDR estimates, and the feedstock sampling protocol.

Feedstock description

Project Developers shall provide a comprehensive qualitative description of the feedstock once for each (in addition to the quantitative Feedstock measurements described below). This description shall include:

• source of the feedstock (GPS coordinates, name of the quarry/mine/site)

• partner companies extracting the feedstock

• additional processing steps undertaken by the project

• general mineralogic composition and heterogeneity (see Feedstock measurements section for detailed composition)

• any jurisdictional regulations around rock spreading frequency, amount and mineral content (e.g. fertilizer guidelines)

• waste status

  • if it is waste, describe its alternative use. This informs the creation of the baseline scenario, to determine whether to include baseline CDR from feedstock storage.

Feedstock measurements

Project Developers shall measure the following characteristics of feedstock described in Tables 1 and 2 on a composite representative sample once for each. The exception is moisture content, which must be measured just before each spreading event.

It is assumed that all feedstock within one feedstock batch has the same characteristics, and does not need to be sampled for each spreading event, as long as feedstock is stored in covered areas protected from moisture.

If exposed to moisture, weathering may occur, altering its previously measured characteristics. In this case, the feedstock stored uncovered shall be considered a new feedstock batch.

CDR potential

Table 1 List of measurements to perform on feedstock to determine CDR potential.

Characteristic	Description
Chemical composition	Concentration of calcium (Ca), magnesium (Mg), potassium (K), sodium (Na), sulfur (S), phosphorus (P), aluminum (Al), silicon (Si), and iron (Fe)
Mineralogical composition	proportion of the different crystalline minerals and (assumed) amorphous phases for silicate feedstocks: amount of carbonate minerals
Particle size distribution and morphology	measure particles with a diameter of greater than 2.0 mm to those with a diameter of 2.5 µm or less
Moisture content	gravimetric water content*

*to be measured from samples taken immediately prior to spreading feedstock

ESDNH

The following measurements shall be taken of feedstock before spreading for the purpose of demonstrating that the project meets Environmental and Social Do No Harm requirements. Project Developers shall compare all measurement results to the thresholds set in the relevant jurisdictional regulations. It shall be transparently stated when no regulation covers the given measurement.

Note that additional analyses and monitoring are required after spreading to monitor potential environmental risks, described in the Monitoring Plan section.

Table 2 List of measurements to perform on feedstock to determine ESDNH compliance.

Characteristic	Description
Chemical composition	Concentration of antimony (Sb), arsenic (As), barium (Ba), beryllium (Be), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), lead (Pb), manganese (Mn), mercury (Hg), nickel (Ni), selenium (Se), silver (Ag), thallium (Tl), uranium (U), vanadium (V) and zinc (Zn)
Mineralogical composition	Concentration of asbestos, asbestiform minerals respirable crystalline silica (RCS) (quartz, cristobalite, and tridymite)*
Radioactivity	Concentration of relevant radionucleotides such as Uranium (U-238 series), Thorium (Th-232 series), Radium (Ra-226, Ra-228), Potassium-40 (K-40), Lead-210 (Pb-210), and Polonium-210 (Po-210). Proof of adherence to jurisdictional regulations regarding radioactivity, such as BSSD (2013/59/Euratom) in the EU or OSHA 1910 Subpart Z in the US.
Particle size distribution	Concentration of particles with a diameter of 2.5 µm or less

*optional measurement. If not measured, safety precautions must be implemented and described to protect workers from RCS

CDR Estimates

Using the CDR measurements described above, and site-specific considerations, Project Developers shall provide the following for ex-ante project validation and for each spreading event:

Maximum potential CDR

Maximum potential CDR of applied feedstock shall be calculated based on the modified Steinor equation, shown below ().

$\textbf{(Eq.1)}\ E_{pot} = \frac{M_{CO_2}}{100} \times \left( \alpha \frac{CaO}{M_{CaO}} + \beta \frac{MgO}{M_{MgO}} + \varepsilon \frac{Na_2O}{M_{Na_2O}} + \theta \frac{K_2O}{M_{K_2O}} + \gamma \frac{SO_3}{M_{SO_3}} + \delta \frac{P_2O_5}{M_{P_2O_5}} \right) \times 10^3 \times \eta$

• $E_{pot}$ represents the maximum CDR potential of a feedstock

• $CaO, MgO, SO_3, P_2O_5, Na_2O$ and $K_2O$ represent the elemental concentrations in the form of oxides

• $M_x$ denotes the molecular mass of each respective oxide $x$

• $\alpha, \beta, \gamma, \delta, \varepsilon, \text{ and } \theta$ represent the relative contributions of each oxide. According to , $\alpha, \beta, \varepsilon, \text{ and } \theta$ are equal to -1; $\gamma$ equals -1; and $\delta$ equals -2.

• $\eta$ represents the molar ratio of CO$_2$ sequestered per divalent cation present in the feedstock. As a default, this may be assumed to be 0.85. See the Measurements section for more details.

Potential CDR over the project lifetime

Potential CDR over the project lifetime, shall be modeled, specifying CDR across any expected crediting period renewals.

This shall include a curve of expected weathering completion (e.g. 10 years after application, it is estimated that 70% of the material has weathered). The results of this modeling are used for informing allocation of upstream impacts in the GHG quantification. The models used shall:

• include at least a consideration of moisture, temperature, and pH in the project region.

• come from in peer-reviewed literature and/or other applications with third-party evaluation.

• link biogeochemical and hydrological processes.

• have already been calibrated and validated with appropriate independent datasets of CDR measurements.

• transparently assess initialization assumptions and model uncertainty, and the resulting effect on CDR estimates.

• include an estimate of CDR loss in the FFZ (i.e. in rivers, surface water, and the ocean).

• use direct measurements of multiple variables to ground-truth models wherever possible.

Feedstock Sampling Protocol

In the Feedstock Characterization Report, Project Developers shall describe and justify the following, considering feedstock heterogeneity and site-specific factors:

• sampling frequency

• how to ensure representative sampling

• number of subsamples to combine into a composite sample

• total amount of sampled material needed to conduct all measurements and obtain precise results

• sample collection and handling methods

For example, if a Project Developer receives one feedstock batch of 1,000 tonnes of waste mine tailing rock from a single feedstock source, and spreads 400 tonnes at at Farm A and 400 tonnes at Farm B in Year 1, they shall submit one Feedstock Characterization Report with:

• one comprehensive qualitative description

• one set of feedstock measurements

• one calculation of CDR estimates

• one description of the feedstock sampling protocol

If they receive another 500 tonnes of rock from the same source 2 months later, it is considered a new feedstock batch. If it is spread at Farm A, then all components listed above must be updated and a separate Feedstock Characterization Report submitted.

If they store the remaining 200 tonnes of rock from the first delivery for one year, in a covered protected area, and in Year 2 spread the additional 200 tonnes at Farm A, then they only need to update the CDR estimate calculations. The other components remain valid for the new spreading event. See the Monitoring requirements for successive spreading event with new feedstock batch section.