Need to return call by / at/between and

. Signature: Project No.: 0317.02.005.510 Page 1 of

Project

Name: 2014 Annual Review

CBI?

Yes

No TELEPHONE CALL RECOR D

Incoming

Outgoing Date: December

16, 2014 Time: 4:30 am

pm

Company

Name: Kennecott Utah Copper/Rio Tinto America

Inc. ERG Staff Name: Eva Knoth

Contact

Name: Kyle Bennett

Tom Nan n ini Contact Phone

Number: 801

- 204

- 2915

801

- 569

- 6466

General

Subject: 2013 TRI Water Releases for TRI 84006KNNCT12300 and 84006KNNCT8362W

TOPICS DISCUSSED AND ACTION TAKEN

I left a message for Mr. Bennett on December 16, 4:30 pm.

Tom Nan nini left a message for me on December 17, 6:30 pm. I left a message from Mr. Nanini at 12:30 pm on

December 19, 2014. He left a subsequent message for me at 1:45 pm and then I called him at 3 pm.

I explained that EPA would like to clarify its interpretation o f the TRI data for silver water releases for two

facilities in Utah: Kennecott Utah Copper Mine Concentrators & Power Plant in Bingham Canyon, UT and

Kennecott Utah Copper Smelter & Refinery in Magna, UT. The facilities reported 500 pounds of silver

relea sed to surface waters in 2013 and have reported the same value in past years. I asked if he could confirm

the values and describe how the releases were estimated for each facility. Mr. Nan n ini said that he would pull

the information together and respond vi a email

.

From: Tom.Nannini@riotinto.com

To: eva.knoth@erg.com

Cc: Ryan.Evans@riotinto.com; Steve.Schnoor@riotinto.com

Subject: Rio Tinto Kennecott TRI inquiry

Received: 12/22/2014 11:31 PM

Eva,

This email serves as formal response to Eastern Research Group’s (ERG) inquiry into Rio Tinto Kennecott

2013 Toxic Release Inventory (TRI) submittal. Rio Tinto Kennecott understands that ERG has been contracted

by the USEPA to review 2013 TRI reports.

Thank you for your request to confirm the quantity of silver releases to water reported in Form R submittals for

Rio Tinto’s MC&P [ Kennecott Utah Copper Mine, Concentrator and Power Plant, Bingham Canyon, UT.

TRIFID: 84006KNNCT12 300] and S&R [ Kennecott Utah Copper Smelter and Refinery, Magna, UT. TRIFID:

84006KNNCT

8362W ] facilities in Salt Lake County, Utah.

We do confirm the estimated 500 pounds reported annually since 2007 for each of these facilities. Our

reporting is based on plant knowledge that silver releases are at least an order of magnitude less than co pper

releases and on historic plant data for silver concentrations in tails deposited in the impoundment. Only a smallNeed to return call by / at/between and

. Signature: fraction of silver deposited to the impoundment would then be released to water. Silver is not one of the

constituents analyzed in wate r samples. Therefore, Rio Tinto Kennecott uses a conservative maximum estimate

of 1,000 pounds of silver released to water, divided equally between the MC&P and S&R facilities at 500

pounds each. Prior to RY2007, the TRI reporting Code B was used to indic ate a range between 11 and 499

pounds for silver releases to water. Every year we verify this assumption with plant personnel through our TRI

continuous improvement process. Should available plant information for silver releases change, we will modify

fu ture Form R submittals accordingly.

We hope this information clarifies and confirms the reported quantity of silver releases to water. Please let us

know if you have any further questions. I can be reached by email or at 801 569 6446 or contact Ryan Eva ns at

801 569 6449.

Regards,

Thomas Nannini

Senior HSE Advisor

Rio Tinto Kennecott

4700 Daybreak Parkway, South Jordan, Utah, 84095, USA

T: +1 (801) 569 6466 M: +1 (801) 230 7884 F: +1 (801) 569 6408

tom.nannini@riotinto.com www.riotintokennecott.com