Everest, as a storyteller, has guarded her secrets well and has offered only a few clues to those hoping to solve this mountaineering mystery. Each clue can and has resulted in differing interpretations, which has led to an even greater level of speculation about the significance of each and the likelihood that Mallory and Irvine reached the summit.
The Ice Ax: The recovery of Irvine's ice ax by the 1933 British expedition can lead to different conclusions, based on one's assumption about how the ax came to be where it was found. Some, believing it was dropped by Irvine during a fall, think it marks the certain high point for Mallory and Irvine and also serves as a point from which to search for Irvine's remains. Others believe that because the ax was found on a fairly flat rock in a setting very amenable to a rest break, it was more likely either forgotten by Irvine after a brief stop or was left there intentionally after he found the instrument of little use on the bare, rocky terrain.
Wang Hongbao's Report: In the 75 years following the 1924 expedition, only one additional piece of information about Mallory and Irvine emerged. A climber named Wang Hongbao participated in a 1975 Chinese expedition. During his search for a lost climber near the Chinese Camp 6, Wang reportedly found a body that he described to his teammates as "English." His reports did not get repeated to others and this information did not reach outsiders until 1979. Then, while participating in a Chinese-Japanese expedition, Wang again briefly recounted his story to a Japanese climber, Hasegawa. He again indicated the body was "English" and with hand gestures implied the face or cheeks had been pecked by birds. The next day, Wang was killed in an avalanche, leaving his sketchy report to Hasegawa as the fullest account of this incident ever reported.
Since no Western climbers or "English" had perished on Everest prior to 1975 other than Mallory and Irvine, if Wang's account was to be believed, then the body he found must have been one of them. Wang's reported find within only 20 minutes of his 1975 Camp 6 served as the basis for the target search area for the 1999 Mallory and Irvine research Expedition team. Based on Hemmleb's research they were able to locate the 1975 Chinese Camp 6 and use that as a starting point for their search. The "English" body (Mallory) that the 1999 team ultimately did discover was such a great distance from the 1975 Camp 6 that it is not likely to be the same body reported by Wang.
The Second Step: Many experienced Everest climbers believe Mallory and Irvine would have been unable to surmount the most technically difficult part of the route to the summit via the Northeast Ridge: the Second Step. The headwall at the top of this rock formation severely challenged a fairly inexperienced 1960 Chinese expedition that finally surmounted it after hours of struggle, with one climber ultimately removing his boots and gloves and standing on the shoulders of his teammate in order to gain the top (only to then lose his hands and feet to frostbite.) The 1975 Chinese expedition wisely erected an aluminum ladder on this portion of the route, which has been used by climbers ever since. In 1999, Conrad Anker attempted to climb this pitch without aid of the Chinese ladder in order to evaluate the difficulty and was essentially able to do it in a matter of minutes.
Some experts view the issue in this way: Mallory was probably a better climber than the 1960 Chinese and he was certainly not the climber that
Conrad Anker is today. So Mallory's ability to surmount the Second Step probably falls somewhere in between these two extremes, and the best
evidence to support his ability to climb it will be the discovery of 1924 oxygen cylinders above this point.
The Goggles: The 1999 research expedition recovered Mallory's climbing goggles from his pants pocket, slightly bent or crushed in the fall. This almost certainly indicates that Mallory was climbing after dark, or in very low light conditions, at the time of his fall. If, as many believe, Mallory and Irvine were turned back by the Second Step, they would have had plenty of time to return to their high camp before dark.
That they were climbing after dark indicates that they probably had pushed on through the day and well beyond a point of safe return, possibly even to the summit. Having left their lanterns and torches in their tent (to be discovered by the 1933 team) their decision to push on beyond a reasonable turnaround time led them to a return trip in virtually impossible conditions.
The Photo: Mallory was believed to have carried a photo of his wife Ruth, which he reportedly intended to place on the summit of Everest. That no such photo was found within his packet of personal notes and letters indicates to some that he may actually have reached the summit and left the photo there.
The Oxygen Inventory: One of the most compelling items recovered by the 1999 team was the detailed inventory maintained by Mallory of all provisions at all camps. From these notes the 1999 team was able to ascertain that Mallory and Irvine had available to them at their high camp more oxygen cylinders than previously known. The existence of additional O2 cylinders, if taken by Mallory and Irvine on summit day, would have greatly extended the time and distance that they would
have been able to climb on their summit bid. The 1924 cylinder recovered by Tap Richards in 1999 was almost certainly one of the first cylinders they used, which they discarded after emptying it.