Question: Which American rock climber responsible for locating the body of George Mallory on Everest failed in his attempt to climb over the west ridge of Mount Epperly?

Context paragraphs:
Eric Simonson (mountaineer): Eric Simonson is an American mountain guide who has conducted many expeditions around the globe, including over 30 to the Himalayas.  He organized the Mallory and Irvine Research Expedition in 1999 to attempt to resolve the mystery of the outcome of the 1924 British Mount Everest expedition and discovered the body of its lead climber George Mallory.

Mount Epperly: Mount Epperly is a 4359 m or perhaps 4512 m mountain in the Sentinel Range, Ellsworth Mountains in Antarctica.  It overlooks Cervellati Glacier to the northeast and Ramorino Glacier to the east-northeast.  The peak was first climbed by Erhard Loretan, solo over the 2100 m south face, on December 1, 1994.  Loretan returned the next year and reclimbed the route for a film.  In 1999, the American climbers Conrad Anker and Jim Donini failed in their attempt over the west ridge.  The third successful ascent was by the Chilean Camilo Rada and Australian Damien Gildea via a new route over the south face in December 2007.  Their GPS measurements on top suggested a height 153 m above the official one.

1924 British Mount Everest expedition: The 1924 British Mount Everest expedition was—after the 1922 British Mount Everest expedition—the second expedition with the goal of achieving the first ascent of Mount Everest.  After two summit attempts in which Edward Norton set a world altitude record of 28,126 feet (8572m), the mountaineers George Mallory and Andrew "Sandy" Irvine disappeared on the third attempt.  Their disappearance has given rise to the long-standing unanswered question of whether or not the pair climbed to the summit.  Mallory's body was found in 1999 at 26,760 feet (8155 m), but the resulting clues did not provide conclusive evidence as to whether the summit was reached.

Conrad Anker: Conrad Anker (born November 27, 1962) is an American rock climber, mountaineer, and author.  He is famous for his challenging ascents in the high Himalaya and Antarctica.  He is the team leader of The North Face climbing team.  In 1999 he located George Mallory's body on Everest as a member of a search team looking for the remains of the legendary British climber.  He lives in Bozeman, Montana.

The Wildest Dream: The Wildest Dream is a 2010 theatrical-release feature documentary film about the British climber George Mallory who disappeared on Mount Everest in 1924 with his climbing partner Andrew Irvine.  The film interweaves two stories, one about climber Conrad Anker (who discovered Mallory's body lying on Everest in 1999) returning to Everest to investigate Mallory's disappearance and the other a biography of Mallory told through letters (read by Ralph Fiennes and Natasha Richardson), original film footage from the 1920s and archival photos.  The film was released in the US and on giant screen cinemas around the world by National Geographic Entertainment in August 2010 as The Wildest Dream: Conquest of Everest.  The film was released in the UK by Serengeti Entertainment in September 2010 as "The Wildest Dream".

2007 Altitude Everest expedition: The 2007 Altitude Everest expedition, led by the American climber Conrad Anker, arrived at Base Camp below the north face of Everest in May 2007 and retraced the last journey of British climber George Mallory.  On 8 June 1924, Mallory, along with his climbing partner Andrew 'Sandy' Irvine, set out for the summit of Everest but disappeared from view short of the summit.  The mystery of whether they could have been the first climbers to reach the world's highest point has never been resolved.  Anker and his colleagues investigated what happened to them, testing out the durability of their clothing and equipment to establish whether Mallory and Irvine could have reached the summit in the conditions they faced in 1924.

Mallory and Irvine Research Expedition: The goal of the Mallory and Irvine Research Expedition of 1999 was to discover evidence of whether George Mallory and Andrew Irvine had been the first to summit Mount Everest in their attempt of 8–9 June 1924.  The expedition was organized by regular Everest expedition leader Eric Simonson and advised by researcher Jochen Hemmleb, with a team of climbers from the U.S., the United Kingdom, and Germany.  Hemmleb's investigations of sketchy reports of earlier sightings and photographs had led him to identify what he believed was the area in which Irvine's body lay, some distance below where his ice axe had been found by Percy Wyn-Harris on the expedition led by Hugh Ruttledge in 1933.  The team hoped in particular to find a camera on Irvine's body which, had the pair been successful, should have contained a picture of the summit.  Within hours of commencing the search on 1 May 1999, Conrad Anker found a body on the North Face, at 8,155 m; but to their surprise it was that of Mallory, not Irvine.

Paths of Glory (Archer novel): Paths of Glory is a novel by English author Jeffrey Archer based on the story of George Mallory who died attempting to climb Everest in the 1920s.  It was published by St. Martin's Press on 3 March 2009.  It fictionally supports the claims that George Mallory, an Englishman, was the first to conquer Mount Everest — before Sir Edmund Hillary.

Epperly Ridge: Epperly Ridge ( ) is a rock ridge that extends northeast for 4 nmi from Mount Epperly, in the Sentinel Range of the Ellsworth Mountains.  It was named by the Advisory Committee on Antarctic Names in 2006 in association with Mount Epperly.

Chris Sharma: Chris Omprakash Sharma (born April 23, 1981) is an American rock climber.  In 2007, NPR wrote that Sharma had been described as the world's best rock climber.  He is known for being the world's first climber to redpoint a 9b (5.15b) route ("Jumbo love", 2008) and the second to climb a 9a+ (5.15a) and a 9b+ (5.15c) route ("Realization" in 2001 and "La Dura Dura" in 2013).  He is also known for climbing the world's first 9a+ (5.15a) and 9b (5.15b) deep-water solo routes ("Es Pontàs" in 2007 and "Alasha" in 2017).  He bolted and first ascended many of the hardest lines of the Cataluña region in Spain.  In 2015, he opened the gym Sharma Climbing BCN in Barcelona.

Supporting paragraphs: Mount Epperly Conrad Anker
Answer: Conrad Anker